HomeMy WebLinkAboutDiamond Bar General Plan 2040ADOPTED DECEMBER 17, 2019
CITY COUNCIL RESOLUTION NO. 2019-44
2040
2040
ADOPTED DECEMBER 17, 2019
CITY COUNCIL RESOLUTION NO. 2019-44
Prepared by
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ACKNOWLEDGEMENTS
The City would like to thank everyone involved in the making of this General
Plan, including the community members for their invaluable contributions,
dedication and service to shaping the future of our great community.
CITY COUNCIL
Steve Tye, Mayor
Nancy A. Lyons, Mayor Pro Tem
Andrew Chou, Council Member
Carol Herrera, Council Member
Ruth M. Low, Council Member
Jimmy Lin, Former Council Member
PLANNING COMMISSION
Naila Barlas, Chair
Frank Farago, Vice-Chair
Jennifer “Fred” Mahlke, Commissioner
Kenneth Mok, Commissioner
William Rawlings, Commissioner
Raymond Wolfe, Former Commissioner
GENERAL PLAN ADVISORY
COMMITTEE
Mark St. Amant, Chair
Brian Worthington, Vice-Chair
Larry Black
David Busse
Teruni Evans
Mahendra Garg
Amy Harbin
Ching Liu
Cindy Liu
Lee Mao
Michael Ramirez
Victor Ramirez
Gil Rivera
Paul Sherwood
Tony Torng
Joyce Young
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CITY STAFF
Daniel Fox, City Manager
James DeStefano, Former City Manager
Ryan McLean, Assistant City Manager
Greg Gubman, AICP, Community Development Director
David Liu, Public Works Director
Ryan Wright, Parks & Recreation Director
Grace Lee, Senior Planner
Marsha Roa, Public Information Manager
Stella Marquez, Administrative Coordinator
Natalie Espinoza, Associate Planner
Mayuko Nakajima, Associate Planner
Cecilia Arellano, Public Information Coordinator
CONSULTANT TEAM
Dyett & Bhatia Urban and Regional Planners
Fehr & Peers
Arellano Associates
ESA
Urban Field Studio
Pro Forma Advisors, LLC
TKE Engineering, Inc.
CITY OF DIAMOND BAR
21810 Copley Drive
Diamond Bar, CA 91765
www.DiamondBarCA.gov
Adopted December 17, 2019
Resolution No. 2019-44
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TABLE OF CONTENTS
1 INTRODUCTION ........................................................................................1-1
1.1 Scope and Purpose ..................................................................................................1-2
1.2 Planning Context ......................................................................................................1-5
1.3 Planning Process .....................................................................................................1-10
1.4 Vision and Guiding Principles ................................................................................1-15
1.5 Plan Organization....................................................................................................1-17
1.6 Related Documents ...............................................................................................1-20
1.7 Administration ........................................................................................................1-22
2 LAND USE & ECONOMIC DEVELOPMENT ................................................2-1
2.1 Introduction ..............................................................................................................2-2
2.2 Land Use ....................................................................................................................2-4
2.3 Economic Development ........................................................................................2-34
3 COMMUNITY CHARACTER & PLACEMAKING ........................................3-1
3.1 Introduction ..............................................................................................................3-2
3.2 Citywide Character and Design .............................................................................3-3
3.3 Focus Areas .............................................................................................................3-21
4 CIRCULATION ..........................................................................................4-1
4.1 Introduction ..............................................................................................................4-2
4.2 Transportation Network ...........................................................................................4-4
4.3 Vehicle Circulation ................................................................................................4-13
4.4 Pedestrian and Bicycle Circulation .....................................................................4-21
4.5 Public Transportation .............................................................................................4-30
4.6 Parking ....................................................................................................................4-34
4.7 Emergency Access ................................................................................................4-36
4.8 Goods Movement ...................................................................................................4-36
5 RESOURCE CONSERVATION ...................................................................5-1
5.1 Introduction ..............................................................................................................5-2
5.2 Open Space ..............................................................................................................5-4
5.4 Biological Resources ..............................................................................................5-10
5.5 Water Resources .....................................................................................................5-33
5.6 Air Quality ...............................................................................................................5-38
5.6 Cultural Resources .................................................................................................5-44
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6 PUBLIC FACILITIES & SERVICES ................................................................6-1
6.1 Introduction ..............................................................................................................6-2
6.2 Parks and Recreation ...............................................................................................6-4
6.3 Schools and Community Facilities .......................................................................6-17
6.4 Utilities .....................................................................................................................6-22
7 PUBLIC SAFETY .........................................................................................7-1
7.1 Introduction ..............................................................................................................7-2
7.2 Seismic and Geologic Hazards ..............................................................................7-4
7.3 Flood Hazards and Protection................................................................................7-11
7.4 Fire Hazards .............................................................................................................7-15
7.5 Hazardous Materials and Operations ..................................................................7-24
7.6 Public Safety Services............................................................................................7-29
7.7 Emergency and Disaster Management...............................................................7-34
7.8 N oise ........................................................................................................................7-38
8 COMMUNITY HEALTH & SUSTAINABILITY ................................................8-1
8.1 Introduction ..............................................................................................................8-2
8.2 Public Health and Environmental Justice ..............................................................8-4
8.3 Climate Change and Greenhouse Gases ...........................................................8-18
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LIST OF FIGURES
1 INTRODUCTION ........................................................................................1-1
Figure 1-1: Regional Setting .............................................................................................1-7
Figure 1-2: Planning Area ................................................................................................1-8
2 LAND USE & ECONOMIC DEVELOPMENT ................................................2-1
Figure 2-1: Planning Area Land Use Distribution ...........................................................2-5
Figure 2-2: Land Use Diagram .......................................................................................2-10
Figure 2-3: Jobs in the Top 15 Industry Sectors (2015) ................................................2-37
Figure 2-4: Top Employers (2015) ..................................................................................2-37
Figure 2-5: Diamond Bar Population Growth, 1990 - 2040 .........................................2-38
Figure 2-6: Historic Per Capita Retail Spending (2005 - 2014) ...................................2-39
3 COMMUNITY CHARACTER & PLACEMAKING ........................................3-1
Figure 3-1: Urban Design Framework .............................................................................3-5
Figure 3-2: Neighborhood Mixed-Use Focus Area Concept Illustration ..................3-22
Figure 3-3: Town Center Mixed-Use Focus Area Concept Illustration ......................3-24
Figure 3-4: Transit-Oriented Mixed Use Focus Area Concept Illustration ................3-25
4 CIRCULATION ..........................................................................................4-1
Figure 4-1: Circulation Diagram ......................................................................................4-5
Figure 4-2: Proposed Bicyle Network ...........................................................................4-23
Figure 4-3: Transit Lines and Facilities ..........................................................................4-31
Figure 4-4: Goods Movement .......................................................................................4-37
5 RESOURCE CONSERVATION ...................................................................5-1
Figure 5-1: Open Space Network ...................................................................................5-5
Figure 5-2: Natural Communities ...................................................................................5-11
Figure 5-3: Special Status Plants ...................................................................................5-28
Figure 5-4: Special Status Animals ...............................................................................5-29
Figure 5-5: Watersheds and Surface Water .................................................................5-35
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6 PUBLIC FACILITIES & SERVICES ................................................................6-1
Figure 6-1: Existing and Planned Parks and Recreation Facilities ..............................6-8
Figure 6-2: Existing and Proposed Trail Network ..........................................................6-11
Figure 6-3: Schools and Other Public Facilities ..........................................................6-19
Figure 6-4: Existing Sanitary Sewer System .................................................................6-28
Figure 6-5: Existing Storm Drain System .......................................................................6-29
7 PUBLIC SAFETY .........................................................................................7-1
Figure 7-1: Steep Slopes ...................................................................................................7-6
Figure 7-2: Regional Faults ..............................................................................................7-7
Figure 7-3: Liquefaction and Landslide Hazards...........................................................7-8
Figure 7-4: Flood Zones ...................................................................................................7-12
Figure 7-5: Fire Threat ......................................................................................................7-18
Figure 7-6: Fire Hazard Severity Zones ..........................................................................7-19
Figure 7-7: Wildfire Perimeters 1928 – 2019 ..................................................................7-20
Figure 7-8: Hazardous Materials and Sites ..................................................................7-26
Figure 7-9: Public Safety Facilities ................................................................................7-31
Figure 7-10: Typical Noise Levels in the Environment .................................................7-40
Figure 7-11: Existing Noise Contours (2016) ..................................................................7-42
Figure 7-12: Projected Noise Contours (2040) .............................................................7-43
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6 PUBLIC FACILITIES & SERVICES ................................................................6-1
Figure 6-1: Existing and Planned Parks and Recreation Facilities ..............................6-8
Figure 6-2: Existing and Proposed Trail Network ..........................................................6-11
Figure 6-3: Schools and Other Public Facilities ..........................................................6-19
Figure 6-4: Existing Sanitary Sewer System .................................................................6-28
Figure 6-5: Existing Storm Drain System .......................................................................6-29
7 PUBLIC SAFETY .........................................................................................7-1
Figure 7-1: Steep Slopes ...................................................................................................7-6
Figure 7-2: Regional Faults ..............................................................................................7-7
Figure 7-3: Liquefaction and Landslide Hazards...........................................................7-8
Figure 7-4: Flood Zones ...................................................................................................7-12
Figure 7-5: Fire Threat ......................................................................................................7-18
Figure 7-6: Fire Hazard Severity Zones ..........................................................................7-19
Figure 7-7: Wildfire Perimeters 1928 – 2019 ..................................................................7-20
Figure 7-8: Hazardous Materials and Sites ..................................................................7-26
Figure 7-9: Public Safety Facilities ................................................................................7-31
Figure 7-10: Typical Noise Levels in the Environment .................................................7-40
Figure 7-11: Existing Noise Contours (2016) ..................................................................7-42
Figure 7-12: Projected Noise Contours (2040) .............................................................7-43
LIST OF TABLES
1 INTRODUCTION ........................................................................................1-1
Table 1-1: Relationship between General Plan Elements and State
Requirements ....................................................................................................................1-5
2 LAND USE & ECONOMIC DEVELOPMENT ................................................2-1
Table 2-1: Existing Land Uses in the Planning Area .......................................................2-6
Table 2-2: Land Use Density/Intensity Standards Summary Table .............................2-16
Table 2-3: Potential Planning Area Buildout by 2040 ..................................................2-17
Table 2-4: Population Trends 1990 - 2016 .....................................................................2-35
Table 2-5: Projected Employment Growth by Non-Residential
Land Use Category, 2016-2040 .....................................................................................2-39
4 CIRCULATION...........................................................................................4-1
Table 4-1: Hierarchy of Streets and Street Standards ...................................................4-7
Table 4-2: Level of Service Definitions .........................................................................4-14
5 RESOURCE CONSERVATION ....................................................................5-1
Table 5-1: Special Status Plant Species Occuring or Potentially
Ocurring within the Planning Area ...............................................................................5-15
Table 5-2: Special Status Plant Species Occuring or Potentially
Ocurring within the Planning Area ...............................................................................5-18
Table 5-3: South Coast Air Basin Attainment Status (Los Angeles County) ..............5-39
Table 5-4: Previously Recorded Cultural Resources ...................................................5-48
6 PUBLIC FACILITIES & SERVICES .................................................................6-1
Table 6-1: Parkland Inventory (2019) ..............................................................................6-6
Table 6-2: Existing and Proposed Trail Network (2019) ...............................................6-10
Table 6-3: Water Usage .................................................................................................6-25
Table 6-4: 2015 Projected Water Supply vs. Water Usage, Walnut
Valley Water District .......................................................................................................6-26
7 PUBLIC SAFETY ..........................................................................................7-1
Table 7-1: Community Noise Compatibility Matrix ....................................................7-44
8 COMMUNITY HEALTH & SUSTAINABILITY .................................................8-1
Table 8-1: Percentile Ranks for Select Pollution Burden Indicators
in Diamond Bar Disadvantaged Communities ...........................................................8-10
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Diamond Bar General Plan 2040 | INTRODUCTION 1-1
INTRODUCTION 1.0
Diamond Bar is a scenic
community located on the
eastern edge of Los Angeles
County, within minutes of
Orange, Riverside, and San
Bernardino counties. With
its origin as a center for
ranching perched among a
landscape of rolling hills in
the East San Gabriel Valley,
suburban-style growth later
established Diamond Bar as a
residential community known
for its friendly country-living
atmosphere, abundant open
spaces, exceptional public
facilities, well-maintained
parks and hiking trails, and
excellent schools.
INTRODUCTION 1.0
1-2 INTRODUCTION | Diamond Bar General Plan 2040
1.1 SCOPE AND PURPOSE
PURPOSE OF THE GENERAL PLAN
State planning law requires that
each city and county adopt a
comprehensive, long-term general
plan for the physical development
of any lands in its jurisdiction, and
for any land outside its boundaries
which bears relation to its planning
(Government Code Section
65300). The Diamond Bar General
Plan establishes the community’s
long-term vision for development
and includes policies to carry
out that vision by directing future
growth in the city. Policies in the
Plan guide decision-making and
activity related to development,
such as land use, transportation,
conservation, environmental
quality, recreation, public services,
and safety. The General Plan has
been adopted by the City Council
and serves to:
• Establish a long-range vision
that reflects the goals and
desires of the Diamond Bar
community;
• Provide City departments, the
Planning Commission, and the
City Council with strategies
and implementing actions to
achieve the vision;
• Provide a basis for evaluating
whether individual
development proposals and
public projects are in harmony
with the General Plan vision
and policies;
Looking to the future, Diamond
Bar residents seek to maintain
what they love about the city,
including its open spaces, rural
character, and family-friendly
neighborhoods. Diamond Bar
residents also desire to create
new opportunities and places for
residents to gather, play, live, and
work. The city must also contend
with the pressures of regional
growth and its related impacts on
traffic, air quality, the demand
for housing and jobs, and the
loss of open spaces, as well as
the potential effects of climate
change and natural disasters.
Additionally, the continued
need to deliver high-quality
city programs and services will
be shaped by the community’s
changing demographics.
This General Plan is a dynamic
policy document intended to
guide the long-term development
of the City of Diamond Bar. The
Plan reflects the community’s
values and desires, as expressed
in a broad vision for the future,
and addresses important issues
such as land use and urban
design, economic development,
circulation, resource conservation,
public facilities and services,
safety, public health, and
sustainability.
Diamond Bar General Plan 2040 | INTRODUCTION 1-3
INTRODUCTION 1.0
GENERAL PLAN REQUIREMENTS
The State of California grants
local governments the authority
to control land use decisions
within their jurisdictions. Thus,
cities have considerable flexibility
in preparing their general plans
as long as they meet the basic
requirements of State planning
law. The California Government
Code establishes both the content
of general plans and rules for
their adoption and subsequent
amendment. Together, State law
and judicial decisions establish
three overall guidelines for
general plans, which should
be comprehensive, internally
consistent, and long-range.
• Provide standards and
guidance to allow City
departments, other public
agencies, and private
developers to design projects
that are consistent with the
General Plan vision and
policies;
• Provide the basis for
establishing other
implementing plans and
programs, such as the Zoning
Ordinance, subdivision
regulations, specific and
master plans, and the Capital
Improvement Program.
State law requires that a variety
of City actions be consistent
with the General Plan. Regular
ongoing use and review of the
General Plan is therefore essential.
Successful implementation of the
General Plan requires effective
communication among City staff,
the community, and City decision-
makers.
In 1989,
Diamond Bar
became the
86th city in
Los Angeles
County.
1-4 INTRODUCTION | Diamond Bar General Plan 2040
State law requires all general
plans to include seven mandatory
elements: land use, circulation,
conservation, open space,
safety, noise, and housing. The
combination of two or more
mandated elements is permitted.
As housing elements are required
to be updated more frequently
on a State-mandated cycle, the
Diamond Bar Housing Element is
provided under separate cover.
Table 1-1 shows where required
elements can be found in the
Diamond Bar General Plan.
Government Code Section 65303
provides that a general plan may
include any other elements which,
in the judgment of the legislative
body, relate to the development
of the city. The City of Diamond
COMPREHENSIVE
The General Plan must be geographically comprehensive. That is, it
must apply throughout the entire incorporated area and other areas
that the City determines are relevant to its planning. The General
Plan must also address the full range of issues that affect the city’s
physical development.
INTERNALLY CONSISTENT
The General Plan must fully integrate its separate parts and relate
them to each other without conflict. All adopted portions of the
General Plan, whether required by State law or not, have equal legal
weight. None may supersede another, so the General Plan must
resolve conflicts among the provisions of each element. “Horizontal”
consistency applies as much to figures and diagrams as to the
General Plan text. It also applies to data and analysis as well as
policies.
LONG RANGE
The general plan must take a long-term perspective as anticipated
development will affect the city and the people who live or work
there for years to come.
Diamond Bar General Plan 2040 | INTRODUCTION 1-5
INTRODUCTION 1.0
Table 1-1: Relationship between General Plan Elements
and State Requirements
Required Element Location in General Plan
Land Use Chapter 2: Land Use and Economic Development
Circulation Chapter 4: Circulation
Conservation Chapter 5: Resource Conservation
Open Space Chapter 5: Resource Conservation
Safety Chapter 7: Public Safety
Noise Chapter 7: Public Safety
Housing Chapter 9: Provided under separate cover
Bar has determined that economic
development, community
character, public facilities and
services, and community health
and sustainability are critical
issues tied to future growth in the
community and has included these
additional elements in the chapters
of the General Plan.
HORIZON YEAR
Given the long-range requirement,
the Diamond Bar General Plan
establishes a horizon year of 2040,
representing a reasonable time
period in which to plan for the
city’s next major phase of growth,
change, and investment. The
horizon year is not an end point for
the Plan or its policies, but provides
a context for short-, medium-, and
long-term decision-making.
1.2 PLANNING CONTEXT
REGIONAL LOCATION
The City of Diamond Bar is
located on the eastern edge of
Los Angeles County in the San
Gabriel Valley. With convenient
access to State Route 57 (SR-57)
and SR-60, Diamond Bar is within
30 miles driving distance of the
cities of Los Angeles, Riverside,
and Irvine, making it a desirable
part of the region to live and work.
Diamond Bar is bounded by the
cities of Industry and Pomona to
the north and Chino Hills to the
east, and unincorporated Los
Angeles County to the south and
west. The western edge of the city
lies at the intersection of SR-57
and SR-60, with SR-57 connecting
the city to Interstate 10 (I-10) one
and a half miles to the north and
SR-60 connecting to SR-71 roughly
two miles to the east. The Industry
Metrolink Station lies on Diamond
Bar’s northern border with the City
of Industry, providing east-west
transit connections to Los Angeles
and Riverside. The regional setting
is depicted in Figure 1-1.
1-6 INTRODUCTION | Diamond Bar General Plan 2040
SPHERE OF INFLUENCE
The SOI is defined as the ultimate physical boundary and service
area envisioned for the City, and encompasses both incorporated
and unincorporated territory. The Los Angeles County Local
Agency Formation Commission (LAFCO) reviews and approves
proposed boundary changes and annexations affecting the SOI.
The SOI boundary, which has remained relatively constant since
it was first approved in 1990, includes part of Tonner Canyon, an
undeveloped wooded canyon that stretches from SR-57 east to
the San Bernardino county line.
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Figure 1-1: Regional Setting
City of Diamond Bar
Parks/Open Space
Freeways
Highways
Rail and Light Rail
PLANNING AREA
The Planning Area for the General
Plan, shown in Figure 1-2, is defined
as the land area addressed by the
General Plan’s policies and land
use designations. The Planning Area
encompasses 13,039 acres, of which
9,526 acres (73 percent) is in the
city limits and the remaining 3,513
acres (27 percent) is in the Sphere
of Influence (SOI). It is bounded by
the cities of Industry and Pomona to
the north, Pomona and Chino Hills
to the east, and Brea to the south,
and unincorporated Los Angeles
County to the west. While Diamond
Bar does not have jurisdiction
in areas outside of its city limits,
general plans commonly consider
land outside a city’s jurisdictional
boundaries that “bear relation to its
planning” (California Government
Code Section 65300). This typically
includes a city’s SOI and may also
include additional land.
CITY HISTORY
The area now known as the City of
Diamond Bar began as “Rancho
Los Nogales” (Ranch of the Walnut
Trees) after a Mexican land grant
in 1840. In 1918, after changes in
ownership and fragmentation,
portions of the original rancho
were reassembled as Diamond
Bar Ranch. The ranch continued
to be used mainly for agriculture
until 1956, when Christiana Oil
Corporation and the Capital
Oil Company (a subsidiary of
the Transamerica Corporation)
purchased the land and created a
comprehensive development plan,
making it one of the first master-
planned communities in Los Angeles
County. Suburbanization across
the region in the 1960s spurred
Diamond Bar General Plan 2040 | INTRODUCTION 1-7
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LOS ANGELES COUNTY
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LakeMatthewsSantaAnaRiverChino Hills
State Park
Firestone ScoutReservation
PowderCanyon
ArroyoPescadero
Gr it h
P ark
WhittierNarrows
Limestone
Ca nyon
Regional Park
Bommer
Canyon
SAN BERNADINO COUNTY
RIVERSIDE COUNTY
IrvineLake
Fr ank G
Bonellli
Los Angeles
Pasadena
Burbank
Inglewood
Torrance
Downey
Anaheim
Long
Beach
Cerritos
Fullerton
WestCovina
Pomona Ontario
Chino
ly
Orange
Santa
Ana
Irvine
Newport
Beach
HuntingtonBeach
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Hawthorne
Fontana
Be
Corona
Riverside
Jurupa
Valley
Lake
Forest
Laguna
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Laguna
Beach
SanClemente
Oceanside
Lake
Elsinore
Dana
Point
RanchoPalos Verde
Monterey
Park
Alhambra Covina
Clairmont
Arcadia
BaldwinPark
Rancho
Cucamonga
YorbaLinda
Placentia
Carson
SouthGate
CulverCity
Whittier
Glendale
Norwalk
El Monte
Compton
Montebello
Rialto
Avalon
Westminster
Cypress
La Habra
Lakewood
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Figure 1-1: Regional Setting
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Parks/Open Space
Freeways
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Figure 1-1: Regional Setting
1-8 INTRODUCTION | Diamond Bar General Plan 2040
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City of Diamond Bar
Sphere of Influence
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0 0.75 1.50.375
MILESSource: City of Diamond Bar 2016; Dyett & Bhatia, 2016RiversideMetrolinkLin eFigure 1-2: Planning Area
Figure 1-2: Planning Area
Diamond Bar General Plan 2040 | INTRODUCTION 1-9
INTRODUCTION 1.0
housing and population growth in
Diamond Bar, transforming it into
a primarily residential community.
In 1989, after two unsuccessful
attempts, residents voted to
incorporate and on April 18, 1989,
Diamond Bar became Los Angeles
County’s 86th city.
Today, Diamond Bar continues
to be a predominately
residential suburban community.
Development in the city has
tended towards distinct, insulated
neighborhoods with minimal
connections to one another
or to the city’s pockets of
commercial activity. Diamond
Bar has also come to be known
for its destination corporate
and government center at
the confluence of SR-57 and
SR-60, which provides a high
concentration of jobs. As with
other bedroom communities,
Diamond Bar is largely car-
oriented, with residents relying
on cars to access parks, schools,
services, and jobs, in many
cases traveling outside of the
city for entertainment and
work. Community identity in
the city draws heavily from the
cohesiveness of its individual
neighborhoods and its natural
features. Residents take pride in
their hillsides, trees, and open
spaces, which are highlighted in
the city’s public parks and trails.
As the city continues to develop, it
faces many of the same pressures
affecting the region and state,
including worsening traffic,
reduced housing affordability,
and loss of open spaces. Looking
ahead, the community is seeking
ways to stay connected to its rural
beginnings, nurture the physical
and interpersonal connections
that tie the city together, and
foster a sustainable future for
generations to come.
The City of
Diamond
Bar began
as “Rancho
Los Nogales”
(Ranch of the
Walnut Trees)
1-10 INTRODUCTION | Diamond Bar General Plan 2040
1.3 PLANNING PROCESS
The Diamond Bar General Plan was
first adopted in 1995. Since then,
substantial changes to the planning
context of the city have occurred,
including accelerated growth in the
region and shifts in the community’s
demographics, as well as new ways
of thinking about sustainability,
public health, and placemaking.
In light of these changes, the
city undertook a comprehensive
update of the General Plan as an
opportunity to reassess and refine
its long-term vision and identify
the new challenges it will face,
opportunities it will follow, and
approaches it will use to make that
vision a reality. The update process
began in the summer of 2016 and
included the following steps.
PLAN
Fall 2016
Stakeholder
Interviews
Community
Workshop #1
Project Initiation &
Issue Identification
Fall/Winter
Exploring
Alternatives
Alternatives
Evaluation
Community
Workshop #2
Spring 2018
Preferred Plan
& Key Goals
Preliminary
Preferred Plan
Summer/Fall 2019
Draft EIR
Final EIR
Environmental
Impact Report
2016 2017 2018 2019
Existing Conditions,
Trends, & Opportunities
Assessment
Draft Existing
Conditions Report
Final Existing
Conditions Report
Winter 2016 Winter 2018
Draft
Preferred Plan
Final
Preferred Plan
Winter 2019
Public
Review Draft
Public Review
Draft Climate
Action Plan
Hearings
Adopted General
Plan and Climate
Action Plan
Adoption
PROJECT TIMELINE
Diamond Bar General Plan 2040 | INTRODUCTION 1-11
INTRODUCTION 1.0
STAKEHOLDER INTERVIEWS
The planning team conducted a series of interviews with stakeholders representing a
range of local and regional interests. A total of 23 stakeholders participated, including
real estate professionals, local developers, commercial property owners, service
organization representatives, major employers, active community members, former
City Council members, school district administrators, small business owners, and youth
organizations. Stakeholders were given the opportunity to provide their viewpoints on
issues of significance, Diamond Bar’s future, general planning concerns, and other topics
of specific interest. The interviews provided the planning team with insight into issues of
significance for each of the stakeholder groups.
SURVEYS
Two online surveys were conducted over the course of
the planning process. The first survey occurred during the
visioning phase of the project and was intended to explore
community members’ vision for the future of the city as well
as uncover any important issues related to various aspects
of life in Diamond Bar. The survey was available online in
October 2016 in English, Korean, and Chinese, and was also
administered in person at pop-up booths at four different
community events (Barktober Fest, Quail Summit Elementary
School Carnival, Eco Expo, and Diamond Bar High School
Food Festival). The survey received a total of 501 responses.
The second survey took place between October 12
and November 12, 2017 and was focused on gathering
community reactions to the three land use alternatives. The
survey was available online in English, Chinese, and Korean,
and printed versions were also provided at the Whispering
Fountains of Diamond Bar senior housing complex, the
Diamond Bar Center, the public library, and City Hall.
Respondents also had the option of printing out the survey
from the project website to complete by hand and return to
City Hall. A total of 638 people responded to the survey.
OUTREACH ACTIVITIES
Public participation was an essential
part of the General Plan update process.
A variety of outreach activities took
place throughout the planning process
to provide a forum to discuss priorities
and values, allow for the evaluation
of different policy options, and bring
a wide range of community members
and perspectives into the conversation.
Summaries of each activity were made
available to members of the public and
decision-makers and are part of the
public record.
1-12 INTRODUCTION | Diamond Bar General Plan 2040
POP UPS
Over the course of the project, the
City held a number of pop-up events
to raise awareness about the planning
process and gather comments from
a large cross-section of Diamond Bar
residents. During the visioning phase of
the project, the City set up booths at
four community events to promote the
first public workshop and administer
the first survey. During the alternatives
phase, the City focused on popular
destinations such as the high schools
and local markets to promote the
alternatives workshop and survey and
receive feedback.
WORKSHOPS
The first community workshop was held
on November 9, 2016 and used activities
and discussion to collect information
from community members regarding
their visions for the future and their
perspectives on major planning issues
to be addressed during the update.
Around 80 community members
participated in the workshop, while a
number of Planning Commissioners, City
Council members, and General Plan
Advisory Committee members observed
the event. Translation services were
provided for Mandarin, Korean, and
American Sign Language.
The second community workshop took
place on October 19, 2017 and focused
on the three land use alternatives.
Participants received a presentation
on the alternatives and their potential
impacts and took part in discussions
about their preferences and concerns
for each alternative. Approximately
130 community members attended the
workshop, along with members of the
Planning Commission, City Council,
and GPAC who observed. Mandarin
and Korean translation services were
provided.
Diamond Bar community members actively
participated in two community workshops and
discussed their ideas and recommendations for the
2040 General Plan.
Diamond Bar General Plan 2040 | INTRODUCTION 1-13
INTRODUCTION 1.0
NEWSLETTERS
The City used direct mailings to update
community members on progress,
announce upcoming workshops and
surveys, and provide background
information on the process. Two
newsletters were mailed to all Diamond
Bar addresses to announce the start of
the project and introduce the alternatives.
The newsletters were also available online
through the project website. The City also
made announcements through its monthly
newsletter, DBConnection, and news
releases through local outlets and the
City’s website.
WEBSITE
A project website was created to
provide updates on the planning
process, meeting materials and
minutes, documents for public
review, and additional background
information on Diamond Bar and the
General Plan update.The project website provided updates on the planning
process as well as additional resources and background
information on Diamond Bar.
Two newsletters were mailed out to update community
members on the progress of the General Plan.SOCIAL MEDIA TOOLKIT
A social media tool kit was developed
to provide key stakeholders with
copy-ready text for incorporation into
social media sites. The kit included
graphics and content to easily
convey project information. Key
stakeholders were asked to choose
the content that best resonated with
their constituents and contacts list
and copy and paste it to their social
media platforms. The social media
tool kit consisted of post for social
media venues, a brief article, and a
widget that could easily be pinned to
websites and social media platforms.
Stakeholders invited to participate
included educational institutions/
principals, homeowner associations,
and civic and professional groups.
PARTICIPATE!
General Plan Update
Community Workshop
Wednesday, November 9
6:30-8:30 PM | Grand View Ballroom
Diamond Bar Center, 1600 Grand Avenue
Come to the first community workshop to share your vision for the future
of Diamond Bar and give input on major planning issues to be addressed
during the General Plan Update.
The community workshop is just the start—we welcome your participation
in all phases of the General Plan Update. Look for information about the
General Plan at various community events.
Working together, we will create a long-term vision for
Diamond Bar and a roadmap to get there.
Visit www.DiamondBarGP.com for up-to-date news, to join
the email list, complete a short survey, and submit comments.
1-14 INTRODUCTION | Diamond Bar General Plan 2040
General
Planning
Advisory
Committee
(GPAC)
members.
GENERAL PLAN ADVISORY COMMITTEE
A General Plan Advisory Committee
(GPAC) was established by the City
Council to serve in an advisory role
to the Planning Commission and
City Council on matters related to
the General Plan update. The GPAC
was convened to provide input on
the project, reviewing work products
and draft policies, receiving and
considering public comments, and
sharing perspectives based on their
experiences and conversations with
community members before making
recommendations to the Planning
Commission and City Council. The
GPAC was made up of 15 volunteers
from the community who met a total
of 10 times over the course of the
project. All GPAC meetings were
open to the public and allowed for
public comment, and were subject
to the Brown Act.
PLANNING COMMISSION AND CITY COUNCIL
The Planning Commission and City
Council held three public joint study
sessions to provide direction on
the General Plan update. The first,
held on August 10, 2016, covered
the responsibilities of the GPAC and
the identification of issues that the
project should address. The second
meeting, held on March 29, 2017,
covered findings from community
outreach and the existing
conditions research. The third
meeting, held on January 30, 2018,
covered the land use alternatives
and resulted in the selection of the
Preferred Plan.
Upon completion of the Public
Review Draft General Plan and
Environmental Impact Report,
the Planning Commission and
City Council held two joint study
sessions. The Planning Commission
held one public hearing prior to
recommending the Plan to the City
Council. The City Council held one
public hearing and adopted the
General Plan.
Diamond Bar General Plan 2040 | INTRODUCTION 1-15
INTRODUCTION 1.0
1.4 VISION AND GUIDING PRINCIPLES
COMMUNITY VISION
The community vision forms the
basis for the General Plan’s goals
and policies. The vision is an
expression of the collective hopes
and aspirations that members of the
Diamond Bar community have for
the City’s future, and was formed
from all of the input shared by
community members throughout
the planning process.
The
community
vision and
guiding
principles
were formed
by the
community
throughout
the planning
process.
VISION 2040
In 2040 Diamond Bar has a balance of housing and retail
choices, ample job and business opportunities, and an
abundance of options for gathering and recreation. A lively
Town Center provides community members with access to
local services, entertainment, employment, and homes in an
attractive, walkable environment. Diamond Bar continues to
welcome and celebrate cultural diversity, and maintains a
safe, quiet, and family-friendly atmosphere where residents
of all ages and abilities are happy and healthy and live
sustainably. Through thoughtful planning, collaboration,
and stewardship, the community is able to meet the needs
of current and future generations, both growing as a city
and preserving the strong connections and environmental
resources that define its “country living” identity.
1-16 INTRODUCTION | Diamond Bar General Plan 2040
GUIDING PRINCIPLES
The following Guiding Principles
expand upon the community
vision, establishing detailed,
actionable objectives that
support the vision and provide
a foundation for the goals
and policies in the General
Plan. The Guiding Principles
emerged from the various
comments and community
discussions that took place as
part of the planning process.
All of the General Plan’s goals
and policies advance one or
more of the Guiding Principles
in order to achieve the
community vision.
1. Maintain a welcoming, safe
small-town feel. Continue to
cultivate a welcoming, safe
small-town feel that is inclusive
of Diamond Bar’s diverse
and changing population
while preserving existing
neighborhoods.
2. Promote a family-friendly
community. Promote Diamond
Bar’s strong and high performing
school system, support the City’s
youth activities and provide
housing choices for families to
continue to make Diamond Bar
a desirable place for families.
3. Create an inviting Town Center.
Foster the development of a
vibrant, pedestrian-oriented
Town Center in Diamond Bar that
serves as a place for Diamond
Bar’s residents to shop, dine, and
gather.
4. Develop attractive commercial
centers and thriving businesses.
Help Diamond Bar’s existing
commercial centers and
businesses thrive, and attract
new businesses to centrally
located focus areas to serve the
daily needs of residents.
5. Establish a balanced circulation
network. Improve mobility for all
residents, visitors, and workers
by providing a diversity of safe
and convenient transportation
options in a cohesive network,
including active transportation,
transit, and automobile facilities.
6. Support Healthy and Sustainable
Lifestyles. Promote human
and community health and
environmental quality through
the provision of parks and open
spaces, community programs
and services, the preservation of
local and regional environmental
resources, and the reduction of
the greenhouse gas emissions.
7. Foster a strong, collaborative
community. Provide
opportunities for gatherings
among friends, families, and
the community at large and
encourage all members of the
community to participate in
planning and decision-making
for the future.
Diamond Bar General Plan 2040 | INTRODUCTION 1-17
INTRODUCTION 1.0
1.5 PLAN ORGANIZATION
The General Plan is organized by
topic in nine chapters, as follows.
Chapters 2 through 9 constitute
the seven required elements of a
General Plan, as well as optional
elements covering the topics
found to be important to the
community.
• Chapter 1: Introduction. This
chapter outlines the vision
for Diamond Bar’s future and
guiding principles for its growth
and development, provides a
basic context for the General
Plan Planning Area, and covers
the General Plan’s purpose,
relationships to other plans,
organization, and requirements
for administration.
• Chapter 2: Land Use and
Economic Development. This
chapter describes the existing
land use pattern and provides
an explanation of the General
Plan’s approach to citywide
growth. The goals and policies
in this chapter provide the
physical framework for land use
and development in the city. In
addition, this chapter provides
an overview of the population
and employment context in
Diamond Bar, and outlines
goals and policies to support
economic development. The
land use portion of this chapter
is required by State law, while
the economic development
portion is an optional topic.
• Chapter 3: Community
Character and Placemaking.
This chapter provides policy
direction on the desired
character of Diamond Bar at a
citywide scale. It also includes
an urban design framework for
development occurring in the
Town Center, Neighborhood
Mixed Use, Transit-Oriented
Mixed Use, and Community
Core focus areas. This chapter
is an optional General Plan
element.
• Chapter 4: Circulation. This
chapter includes policies and
standards that seek to maintain
safe and efficient circulation
for all modes of travel. It
identifies street improvements,
and addresses walking, biking,
transit, and parking to support
a multi-modal circulation
system. The Circulation Element
is required by State law.
• Chapter 5: Resource
Conservation. This chapter
includes background
information and policies
relating to the conservation
and preservation of open
space resources, biological
resources, water resources,
air quality, and cultural
resources. This chapter satisfies
the requirements for both an
Open Space Element and a
Conservation Element, which
are required by State law.
1-18 INTRODUCTION | Diamond Bar General Plan 2040
• Chapter 6: Public Facilities and
Services. This chapter contains
background information, goals,
and policies related to schools,
community facilities and
libraries, parks and recreation,
water supply and demand,
and public utilities. This chapter
is an optional General Plan
element.
• Chapter 7: Public Safety. This
chapter provides an overview
of the public safety risks in
Diamond Bar related to seismic
and geologic hazards, flood
hazards, hazardous materials
and operations, airport
hazards, fire hazards, and
noise. This chapter satisfies the
requirements for both a Safety
Element and a Noise Element,
which are required by State
law.
• Chapter 8: Community Health
and Sustainability. This chapter
outlines public health concerns
related to the General Plan,
and includes goals and
policies to improve public
health through environmental
justice, active living, healthy
food, social connections, and
sustainable living. This chapter
is an optional General Plan
element.
• Chapter 9: Housing. This
Chapter contains the
policies and programs to
conserve and improve
existing affordable housing,
provide adequate housing
sites, assist in development of
affordable housing, removing
governmental constraints
and promote equal housing
opportunities. As the Housing
Element is required to be
updated on a state-mandated
cycle, the most recently
adopted Housing Element is
incorporated into this Chapter.
The Housing Element is required
by State law.
The Plan should
be reviewed
and revised as
new information
and community
priorities evolve
over time.
Diamond Bar General Plan 2040 | INTRODUCTION 1-19
INTRODUCTION 1.0
Each General Plan element contains the parts
described below.
How land is used underpins the
experience of living, working,
or visiting a place, making
land use a pivotal element of
a General Plan. The Land Use
and Economic Development
Chapter directs the location,
form, and character of future
physical development and
economic growth, shaping
where people will live, work,
and play in Diamond Bar.
LAND USE &
ECONOMIC
DEVELOPMENT 2.0
Goals and Policies: Goals and policies are the core
of the General Plan.
– Goals are statements of broad direction,
philosophy, or standards to be achieved.
– Policies are statements that support the
implementation of the Goals.
– Clarifying Text: Italicized text included with
a policy provides additional information or
examples to clarify the intent or application of
the policy.
Chapters: Each of the General Plan chapters
gathers a number of related topics under
one big-picture umbrella. Several of the
chapters are based on State general plan
requirements, while others are based on
themes derived from the community’s values.
Figures, tables, charts, and
images: The General Plan is
illustrated with figures, tables,
charts, and images to provide
clarifying detail for the topics
covered. In some cases, figures
or tables may establish standards
or policies (such as the Land Use
Diagram or Noise Standards). In
such cases, this is clearly stated or
referenced in a policy.
Topics: Each chapter is divided
into topics that help to organize
background information
and provide context for the
accompanying policies.
1-20 INTRODUCTION | Diamond Bar General Plan 2040
The Plan should
be reviewed
and revised as
new information
and community
priorities evolve
over time.
1.6 RELATED DOCUMENTS
GENERAL PLAN BACKGROUND DOCUMENTS
As part of the planning process,
the City of Diamond Bar developed
a series of documents to inform
decision-makers and members
of the public about the results of
research and analyses related to
the General Plan. These include the
three-volume Existing Conditions
Report, summaries of outreach
activities and findings, the
Alternatives Evaluation, meeting
notes, and others, and can be
referenced on the City of Diamond
Bar’s website.
ENVIRONMENTAL IMPACT REPORT
This General Plan is accompanied
by an Environmental Impact Report
(EIR) prepared according to the
California Environmental Quality
Act (CEQA). The EIR is a program-
level analysis of the potential
environmental effects of the
General Plan and Climate Action
Plan, evaluates alternatives to the
proposed project, and presents
ways to reduce or avoid detrimental
environmental impacts. The EIR
process ensures that environmental
concerns are identified and informs
General Plan policies that can
help to reduce potential adverse
environmental effects of future
development. CEQA requires that
the City Council certify the EIR prior
to adoption of the General Plan.
Future development consistent with
the General Plan will be able to
“tier” its environmental analysis from
the certified EIR, allowing for a more
streamlined development process.
Diamond Bar General Plan 2040 | INTRODUCTION 1-21
INTRODUCTION 1.0
CLIMATE ACTION PLAN
This General Plan is accompanied
by a Climate Action Plan (CAP)
prepared in accordance with the
California Air Resources Board
2017 Climate Change Scoping
Plan and Statewide targets for
greenhouse gas (GHG) emissions
reduction. The CAP is a detailed
analysis of the General Plan’s
contribution to climate change
and associated environmental
and socioeconomic effects. The
CAP provides GHG reduction
targets based on Statewide
thresholds established in AB 32,
SB 32, and the 2017 Scoping Plan.
To establish compliance with
these targets, the CAP includes
an inventory of existing GHG
emissions and a projection of
emissions under the General Plan
in the SB 32 target year 2030 and
General Plan buildout year 2040.
The CAP provides a framework for
the City of Diamond Bar to monitor
progress toward GHG emissions
reduction and meet emissions
targets and recommends optional
strategies for further emissions
reduction. The EIR analyzes
potential environmental effects of
the Climate Action Plan, which will
be adopted with the General Plan.
Therefore, future development
consistent with the General Plan
and Climate Action Plan will be
able to “tier” its environmental
analysis from the certified EIR and
ensure compliance with Statewide
emissions reduction goals.
OTHER PLANS AND IMPLEMENTATION PROGRAMS
The City maintains several
specific, area, and master plans
that cover specific geographic
areas or facilities, such as parks
and trails. Consistent with State
law, these documents, as well as
any implementing programs, are
required to be consistent with the
General Plan. These plans and
programs will be used to provide
further specificity on General
Plan policy and provide more
detailed direction and strategies
for implementation.
1-22 INTRODUCTION | Diamond Bar General Plan 2040
1.7 ADMINISTRATION
IMPLEMENTATION
The General Plan is intended to be
a dynamic document. As part of
implementation, the Plan should
be reviewed regularly regardless
of the horizon year and revised as
new information becomes available
and the community’s priorities
evolve. The Plan should be updated
periodically as site-specific
circumstances change from the
time of writing, to respond to new
State or federal law, or to modify
policies that may become obsolete
or unrealistic over time.
AMENDMENTS TO THE GENERAL PLAN
Changes in policy as well as
the development of unforeseen
opportunities or needs will require
amendment of the General Plan.
California Government Code
Section 65358 provides that no
mandatory element of this General
Plan may be amended more
frequently than four times during
any calendar year. However,
this restriction does not apply to
optional elements, to amendments
needed to comply with a court
decision, or to allow for the
development of affordable housing.
Within this limitation, amendments
may be made at any time as
determined by the Diamond Bar
City Council, and each amendment
may include more than one change
to the Plan.
ANNUAL REPORT
The California Government Code
requires that City staff submit an
annual report to the City Council on
the status of the General Plan and
progress in its implementation. This
report is submitted to the Governor’s
Office on Planning and Research
and the Department of Housing
and Community Development. The
report must include an analysis of
the progress made in meeting the
City’s share of regional housing
needs (identified in the Housing
Element) and local efforts to
remove governmental constraints
to the maintenance, improvement,
and development of affordable
housing. Finally, the report should
also include a summary of all
General Plan amendments adopted
during the preceding year, a
description of upcoming projects or
General Plan issues to be addressed
in the coming year, and a work
program.
LAND USE &
ECONOMIC
DEVELOPMENT 2.0
How land is used underpins the
experience of living, working,
or visiting a place, making
land use a pivotal element of
a General Plan. The Land Use
and Economic Development
Chapter directs the location,
form, and character of future
physical development and
economic growth, shaping
where people will live, work,
and play in Diamond Bar.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-2
2.1 INTRODUCTION
This Land Use and Economic
Development Chapter presents the
proposed pattern for the ultimate
growth and development of the
city for the General Plan horizon
(year 2040) and seeks to ensure that
land use planning and economic
development measures reflect the
community’s priorities for the growth
of the city, conserves open spaces
the natural environment, and
promotes sustainable lifestyles. The
chapter consists of narrative, goals
and policies, as well as a Land Use
Diagram and other figures. It also
includes descriptions of the land
use designations shown on the Land
Use Diagram. Policy text and maps
should be considered collectively
as project approvals or future
amendments are made.
While Diamond Bar has roots as
a suburban community, the Plan
explores the evolution of key focus
areas into more dynamic mixed-
use places that provide housing
for a diversity of Diamond Bar
residents new and old, and provide
opportunities for community
gathering, entertainment and
employment.
Achieving Diamond Bar’s vision for
a more vibrant, connected, livable,
and sustainable community will rely
on more compact redevelopment
with an array of uses at key
opportunity sites, focusing on infill
development to preserve open
space; increasing local retail and
entertainment amenities and
community gathering places
through the establishment of a new
pedestrian-oriented Town Center;
and enhancing livability through
development of neighborhood-
serving commercial uses and parks
accessible to new residential uses
that include an array of housing
options.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-3
2.0 LAND USE & ECONOMIC DEVELOPMENT
RELATIONSHIP TO STATE LAW
State law (Government Code
Section 65302(a)) requires general
plans to include a Land Use
Element. In accordance with
State law, this chapter designates
the general distribution, location
and extent of land for housing,
business, industry, open space,
education, public facilities, and
other categories of public and
private uses of land. It also includes
standards of residential and non-
residential density for the various
areas covered by the General Plan.
RELATIONSHIP TO OTHER ELEMENTS
This chapter has the broadest scope
of all the chapters and provides
the framework for a coherent set
of development policies. Other
chapters of the General Plan
contain goals and policies related
to land use and therefore must
be referenced for a complete
understanding of the purposes,
intentions, and development
requirements embodied in this
chapter. For instance, Chapter
3, Community Character and
Placemaking complements the
land use designations outlined in
this chapter with a framework for
urban design and placemaking.
The street system, street design and
transportation improvements in
Chapter 4, Circulation are intended
to address the transportation
needs that support the land use
pattern established in the Land
Use Diagram. Chapter 6, Public
Facilities and Services establishes
policies and standards for facilities
to serve the population resulting
from residential, employment, and
visitor-serving land uses. Finally,
Chapter 5, Resource Conservation
and Chapter 7, Public Safety
provide further policies related to
open space for the preservation
of natural resources and reducing
safety risks.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-4
2.2 LAND USE
EXISTING LAND USE
Diamond Bar’s overall land use
pattern is characterized by large
swathes of single-family residential
development throughout the City
studded with clusters of multi-family
residential and non-residential
uses. Some of the single-family and
multi-family residential uses in the
city are part of gated communities,
including The Country, an exclusive
gate-guarded community of over
800 large-lot, detached single-
family homes in the southeastern
hills. Multi-family residential
development tends to be located
along the major thoroughfares of
Diamond Bar Boulevard, Golden
Springs Drive, and Brea Canyon
Road, and is often collocated with
non-residential uses.
Commercial and office uses tend
to cluster at intersections (such
as Diamond Bar Boulevard and
Golden Springs Drive, and Diamond
Bar Boulevard and Grand Avenue),
along major thoroughfares, and
along the freeways, and tend to
take the form of shopping centers
and office parks. Industrial uses are
concentrated in the western part of
the city along the border with the
City of Industry, among residential
uses. The Gateway Corporate
Center, a master-planned 255-
acre business park, is located
along the east side of the SR-57/60
confluence. The Gateway center
is home to the South Coast Air
Quality Management District and
several Fortune 500 companies and
is a premier business center in the
region due to its proximity to the
freeways and the Ontario and John
Wayne airports.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-5
2.0 LAND USE & ECONOMIC DEVELOPMENT
Figure 2-1: Planning Area Land Use Distribution
50%
16%
11%
4%4%1%
37%
11%
35%
3%3%1%
Residential
Parks and Open Spaces
Vacant
Commercial, Office, and
Mixed Use
Public and Community Facilities
Industrial
Residential
Parks and Open Spaces
Vacant
Commercial, Office, and
Mixed Use
Public and Community Facilities
Industrial
Planning Area
City Limits
Other
15%
Other
11%
50%
16%
11%
4%4%1%
37%
11%
35%
3%3%1%
Residential
Parks and Open Spaces
Vacant
Commercial, Office, and
Mixed Use
Public and Community Facilities
Industrial
Residential
Parks and Open Spaces
Vacant
Commercial, Office, and
Mixed Use
Public and Community Facilities
Industrial
Planning Area
City Limits
Other
15%
Other
11%
The city is also dotted with a
variety of open space slopes and
areas that follow its many ridges
and hillsides. Public parks and
recreational facilities are found
mostly in the eastern half of the
city, bordering residential uses. The
County-operated Diamond Bar
Golf Course occupies a substantial
portion of land in the north-central
part of the city. Other public
uses, such as schools and utilities,
are relatively evenly distributed
throughout the city. South of
Diamond Bar, the SOI is made up
almost entirely of open space land.
Residential land makes up roughly
half of all land in the city limits
and is the dominant land use in
Diamond Bar. The next-largest
category of land use in the City is
private easements, such as private
streets and HOA-owned open
space areas. The third-largest
category of land use in the city
is parks and open space land,
including land that may not be
suitable for development due
hazardous locations along hillsides
and slopes or other conditions,
followed by public and community
facilities, office uses, commercial
uses, and industrial uses. Existing
land uses as of 2019 are summarized
in Table 2-1, and Figure 2-1 illustrates
the proportion of each type of land
use in the city and Planning Area,
excluding rights-of-way.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-6
Table 2-1: Existing Land Uses in the Planning Area
Existing Use of
Land Category
City of Diamond Bar Sphere of
Influence
Planning Area
Acres %Acres %Acres %
Residential 4,772.4 50.1% - - 4,772.4 36.6%
Single Family Residential -
Detached
4,257.2 44.7% - - 4,257.2 32.7%
Multifamily Residential 479.0 5.0% - - 479.0 3.7%
Mobile Home Park 36.3 0.4% - - 36.3 0.3%
Industrial 71.6 0.8% - - 71.6 0.5%
Light Industrial 44.2 0.5% - - 44.2 0.3%
General Industrial/Warehousing 27.3 0.3% - - 27.3 0.2%
Public and Community Facilities 344.7 3.6% - - 344.7 2.6%
Religious/Institutional Facilities 41.8 0.4% - - 41.8 0.3%
Hospital/Medical Center 12.9 0.1% - - 12.9 0.1%
Schools/Educational Facilities 278.8 2.9% - - 278.8 2.1%
Public Facilities 11.2 0.1% - - 11.2 0.1%
Commercial and Mixed Use 339.6 3.6% - - 339.6 2.6%
Service Station 8.1 0.1% - - 8.1 0.1%
Hotel/Motel/Lodging Commercial 11.9 0.1% - - 11.9 0.1%
Auto Commercial 11.7 0.1% - - 11.7 0.1%
General/Retail Commercial 135.2 1.4% - - 135.2 1.0%
Mixed Commercial & Office Uses 6.9 0.1% - - 6.9 0.1%
Office/Banks/Financial Services 165.7 1.7% - - 165.7 1.3%
Vacant 1,672.9 17.6% 356.7 10.2% 2,029.6 15.6%
Vacant 1,137.0 11.9% 356.7 10.2% 1,493.7 11.5%
Vacant Natural Undeveloped
Areas
535.9 5.6% - - 535.9 4.1%
Parks and Open Spaces 793.1 8.3% 3,156.0 89.8% 3,949.1 30.3%
Parks & Recreation 310.1 3.3% - - 310.1 2.4%
Golf Course 172.4 1.8% - - 172.4 1.3%
Open Space, Greenways, Trails,
Natural Areas
310.6 3.3% 3,156.0 89.8% 3,466.6 26.6%
Other 1,531.4 16.1% - - 1,531.4 11.7%
Utilities 28.0 0.3% - - 28.0 0.2%
Street ROW, Private Roads, etc 1,503.4 15.8% - - 1,503.4 11.5%
Total 9,525.7 100.0% 3,512.6 100.0% 13,038.3 100.0%
Source: City of Diamond Bar, 2016; Los Angeles County Assessor’s Office, 2016.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-7
2.0 LAND USE & ECONOMIC DEVELOPMENT
FOCUS AREAS
The General Plan provides for
four focus areas where major
land use changes are planned to
take place as part of a strategy
to provide walkable mixed-use
activity centers. These focus areas
provide opportunities for infill
development that can incorporate
a range of housing, employment,
and recreational uses to meet the
needs of families, young people,
senior citizens, and residents of all
incomes. These focus areas were
designed in response to community
priorities including a desire for
expanded access to entertainment
and community gathering places,
and the need to accommodate
the City’s growing and diverse
population. New Land Use
designations are proposed for each
of these focus areas to facilitate
their development, as described
under Land Use Classifications,
below.
Town Center
Throughout the General Plan update process, residents of
Diamond Bar have expressed a desire for greater access to
dining, entertainment, and retail establishments within the city.
More specifically, community input indicated a desire for the
concentration of these new establishments within a walkable area
resembling a more traditional downtown. While Diamond Bar has
numerous centers of activity, including the Diamond Bar Center, the
City Hall and Library complex, high schools and various suburban-
style commercial centers, the city lacks a clear community focal
point – a role commonly played by a vibrant downtown.
The Town Center focus area is proposed along Diamond Bar
Boulevard, between SR-60 and Golden Springs Drive, to build on
the success of recent commercial redevelopment in that area.
The Town Center would serve as a center of activity for residents of
Diamond Bar, providing entertainment and retail opportunities and
community gathering spaces in a pleasant, walkable environment.
Mixed Use Neighborhood
The Neighborhood Mixed Use focus area is envisioned as a
combination of residential and ancillary neighborhood-serving
retail and service uses to promote revitalization of the segment of
North Diamond Bar Boulevard between the SR-60 interchange and
Highland Valley Road. The neighborhood has potential to benefit
from its proximity to Mt. San Antonio College and Cal Poly Pomona.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-8
Community Core Overlay
The Community Core focus area covers the existing Diamond Bar
Golf Course, which is currently operated by Los Angeles County.
Should the County choose to discontinue operation of the golf
course or to reduce the size of the golf course, the Community
Core would be the City’s preferred approach to reuse of the site.
The Community Core is envisioned as a master-planned mixed-use,
pedestrian-oriented community and regional destination. The
majority of the northern portion is envisioned to support a park or
consolidated golf course along with additional community or civic
uses. The southern portion is envisioned to accommodate a mix
of uses emphasizing destination and specialty retail, dining, and
entertainment, including opportunities for residential, hospitality,
and community and civic uses. This location would benefit greatly
from proximity to the freeways and nearby commercial uses.
Transit-Oriented Mixed Use
The Transit-Oriented Mixed Use focus area leverages underutilized
sites adjacent to the Metrolink station to provide for higher-density
housing, offices, and supporting commercial uses close to regional
transit. The focus area would allow for growth in employment
opportunities in addition to contributing to housing availability in
the city, and would be a key location to emphasize multi-modal
transportation options tied to land use.
Floor Area Ratio (FAR) refers to the ratio
between a building’s total floor area and
the total area of the site and is used as a
measure of non-residential development
intensity. For instance, as shown in this
illustration, a one-story building occupying
one half of a parcel has an FAR of 0.5; a
two-story building occupying a quarter of
the same parcel also has an FAR of 0.5.
FLOOR AREA RATIO
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-9
2.0 LAND USE & ECONOMIC DEVELOPMENT
LAND USE CLASSIFICATIONS
The General Plan Land Use Diagram
is depicted in Figure 2-2. The
diagram designates land in the
Planning Area according to land
use classifications that describe
allowable uses, densities, intensities,
and other considerations for new
development in those locations.
The Land Use Diagram is a graphic
representation of the General Plan’s
policies regarding growth and
development and is to be utilized
in conjunction with the policies as
a guide to decision making. The
land use classifications are adopted
as General Plan policy and are
intentionally broad to provide a
basis for more detailed direction
in the City’s Zoning Ordinance.
The Zoning Ordinance and the
Zoning Map must be consistent
with the classifications and Land
Use Diagram and prescribes in
greater detail specific uses of the
land and associated development
regulations that apply to property
to further implement the General
Plan. More than one zoning district
may be consistent with a single
General Plan land use category.
State law requires the General Plan
to establish standards of population
density and building intensity
for each land use classification.
Density/intensity standards
regulate how much development
is permitted on a site. Residential
density is expressed as housing units
per gross acre, as described for
each land use. For non-residential
and mixed uses, a maximum
permitted Floor Area Ratio (FAR)—
the ratio of total gross floor area to
total site area—is specified. Density
and intensity standards are listed
below for each classification.
The density/intensity standards do
not require the City to approve
development projects at the top
of the density or intensity range for
each classification. In many cases,
regulations and site constraints
resulting from environmental, safety,
or other considerations may reduce
the development potential of any
given site. Thus, realistically, not all
sites would be expected to develop
to their maximum densities or
intensities.
Table 2-2, summarizes the land use
classifications, including density
and intensity ranges, as well as the
total acreage in each land use
category as mapped on the Land
Use Diagram.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-10
!(T
Significant Ecological Area
DiamondRanch HighSchool
PanteraPark
PanteraE.S.
Carlton J. Peterson ParkGOLDENSPRINGSDRDiamondPointE.S.
Little LeagueField
ArmstrongE.S.
GoldenSpringsE.S.
LorbeerJunior H.S.
SycamoreCanyon Park
Quail SummitE.S.
ChaparralM.S.
Maple HillE.S.Maple HillPark
WalnutE.S.
South PointeM.S.
DiamondBar H.S.EVERGREENSPRI
NGSRDEvergreenE.S.
Castle RockE.S.
HeritageParkPEACEFULHILLSRD
RonaldReaganPark
Star ShinePark
SummitridgePark
Country Park
LarkstonePark
Walnut
Pomona
Industry
LOS ANGELES
COUNTY
ORANGE COUNTY
SAN BERNARDINO
COUNTYRiversideMetrolinkLineMetrolinkStation
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CO PLEYDRBRIDGEGATEDRVALLEYVISTADRROCKRIVERRDDELSOLLNSource: City of Diamond Bar 2019; Dyett & Bhatia, 2019
0 0.5 10.25
MILES
Land Use Designations
Rural Residential
Low Density Residential
Low-Medium Residential
Medium Density Residential
Medium High Density Residential
High Density Residential
High Density Residential-30
Neighborhood Mixed Use
Town Center Mixed Use
Transit Oriented Mixed Use
Light Industrial
General Commercial
Office
Water
School
Public Facility
Park
Golf Course
Open Space
Significant Ecological Area
Private Recreation
Planning Area
Specific Plan
Community Core Overlay
City of Diamond Bar
Sphere of Influence
County Boundary
Figure 2-2: Land Use Plan C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATEFigure 2-2: Land Use Diagram
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-11
2.0 LAND USE & ECONOMIC DEVELOPMENT
RESIDENTIAL
Rural Residential
Allows for residential development at densities of
1.0 dwelling unit per gross acre (1 du/ac), with lower
density for sites with slopes greater than 25 percent,
in accordance with the slope density standard.
Low Density Residential
Allows for single-family detached residential
development reaching a maximum of 3.0 dwelling
units per gross acre (3.0 du/ac).
Low-Medium Residential
Allows for single-family detached residential
development reaching a maximum of 5.0 dwelling
units per gross acre (5.0 du/ac).
Medium Density Residential
Allows for townhome, condominium, apartment,
mobile home, and other multi-family residential
development reaching a maximum of 12.0 dwelling
units per gross acre (12.0 du/ac).
Medium High Residential
Allows for townhome, condominium, apartment, and
other multi-family residential development reaching
a maximum of 16.0 dwelling units per gross acre (16.0
du/ac).
High Density Residential
Allows for high-density condominium, apartment
and other high-density residential development
reaching a maximum of 20.0 dwelling units per gross
acre (20.0 du/ac).
High Density Residential-30
Allows for high-density condominium, apartment,
and other high-density residential development with
a minimum net density of 20.0 dwelling units per
acre (20.0 du/ac) and a maximum net density of 30.0
dwelling units per acre (30.0 du/ac)
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-12
COMMERCIAL, OFFICE, AND INDUSTRIAL
General Commercial
Allows regional, freeway-oriented and/or community
retail and service commercial uses. Development
is to maintain a floor area ratio (FAR) between 0.25
and 1.0.
Office
Allows for office-based working environments
including general, professional, and administrative
offices, and supporting commercial, retail, and
service uses. Development is to maintain an FAR
between 0.25 and 1.0.
Light Industrial
Allows light industrial uses such as manufacturing,
distribution, research and development, business
support services, and commercial uses requiring
more land area than is available under the General
Commercial or Office designations. Development is
to maintain an FAR between 0.25 and 1.00.
MIXED USE
Town Center Mixed Use
Allows and encourages a mix of uses with an
emphasis on community-serving and destination
retail, dining, and entertainment uses. Offices and
professional services, and residential uses are also
permitted. Maximum FAR is 1.5 and a maximum
residential density of 20.0 dwelling units per acre
(20.0 du/ac) is permitted.
Neighborhood Mixed Use
Allows a range of housing types and commercial
uses, with a maximum FAR of 1.25 and a maximum
residential density of 30.0 dwelling units per acre
(30.0 du/ac). General Plan policies further delineate
permitted and desired mix of uses and housing types
based on parcel size and project location.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-13
2.0 LAND USE & ECONOMIC DEVELOPMENT
Transit-Oriented Mixed Use
Allows high density residential live/work units,
office, retail, commercial, and service uses, with
a maximum FAR of 1.5. Residential uses, where
provided, should be at a density ranging from
20.0 to 30.0 dwelling units per acre (20.0 - 30.0 du/
ac) of gross site area. Existing light industrial uses
shall be permitted to remain as conforming uses
in accordance with the Light Industrial land use
designation and associated zoning regulations.
Community Core Overlay
The underlying Golf Course designation permits
continued operation of the present golf course use.
Should the golf course cease operation, this overlay
designation would require a master plan for the
entire golf course property to ensure the orderly and
cohesive implementation of its reuse.
OTHER
Planning Area
Designed to conserve open space resources and
is to be applied to properties where creative
approaches are needed to integrate future
development with existing natural resources. All
proposed development within these designated
areas shall require the formation of a Specific Plan
pursuant to the provisions of Government Code
Section 65450.
Specific Plan
This designation is intended to encourage the
innovative use of land resources and development
of a variety of housing and other development
types, provide a means to coordinate the public
and private provision of services and facilities,
and address the unique needs of certain lands. It
designates large-scale development areas in which
residential, commercial, recreational, public facility,
and other land uses may be permitted, or large
properties (in excess of 10 acres) that are proposed
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-14
to be annexed into the city, where a specific plan
pursuant to the provisions of Government Code
Section 65450 shall be required that will protect
unique biological and open space resources,
create fiscal benefits for the City and enhance its
infrastructure, and minimize future adverse impacts
to both the human and natural environment of the
city and region.
Golf Course
Identifies the Diamond Bar Country Club and Golf
Course.
Park
Existing and future public parks.
Open Space
Provides recreational opportunities, preservation
of scenic and environmental values, protection of
resources (water reclamation and conservation),
protection of public safety, and preservation
of native plant and animal life, habitats, and
ecosystems. This designation includes lands which
may have been restricted to open space use by
map restriction, deed (dedication conditions,
covenant, and/or restriction), by an Open Space
Easement pursuant to California Government Code
Section 51070 et seq. This designation carries with it
a maximum development potential of one single-
family unit per existing privately-owned parcel,
unless construction was previously restricted or
prohibited on such properties by the County of Los
Angeles.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-15
2.0 LAND USE & ECONOMIC DEVELOPMENT
Private Recreation
Identifies major private recreation facilities. May
be applied to lands required to be set aside for
recreational use which have not been dedicated to
or accepted by a public agency; no development
may take place on these lands other than open
space uses specifically permitted by the applicable
Planned Unit Development and/or deed restrictions.
Public Facility
Identifies land for public publicly-owned facilities
and institutions serving the needs of the general
community, such as schools and educational
facilities; government facilities, including public
safety facilities; public utilities; and other facilities of
a public or quasi-public nature. These uses maintain
development standards which do not exceed that of
the most restrictive adjacent designation.
Water
Identifies publicly-owned water facilities.
School
Identifies school facilities.
Significant Ecological Area
Applied to the SOI in observance of the Los Angeles
County’s designation of this area as Significant
Ecological Area 15. The area covered by this
designation is outside of the City’s jurisdiction.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-16
Table 2-2: Land Use Density/Intensity Standards Summary Table
Land Use Density (du/ac)Intensity (FAR)Acreage % of
Planning
Area
CITY OF DIAMOND BAR
Residential
Rural Residential Up to 1.0, with lower density for
sites with slopes greater than
25 percent, in accordance with
the slope density standard.
-1,409 12
Low Density Residential Up to 3.0 -2414 21
Low-Medium Residential Up to 5.0 -779 7
Medium Density
Residential
Up to 12.0 -281 2
Medium High Residential Up to16.0 -199 2
High Density Residential Up to 20.0 -34 <1
High Density
Residential-30
Min. 20.0/Max. 30.0 32 <1
Commercial, Office, and Light Industrial
General Commercial -0.25 – 1.0 123 1
Office -0.25 – 1.0 174 2
Light Industrial 38 <1
Mixed Use
Town Center Mixed Use Up to 20.0 Up to 1.5 45 <1
Neighborhood Mixed Use Up to 30.0 Up to 1.25 38 <1
Transit-Oriented Mixed
Use
Min. 20.0/Max 30.0 Up to 1.5 33 <1
Community Core Overlay Master plan required 168 1 -
Other
Planning Area --707 6
Specific Plan --77 1
Golf Course --168 1
Park --134 1
Open Space Up to 1 du/existing privately-
owned parcel unless restricted
or prohibited
-993 9
Private Recreation --15 <1
Public Facility --63 1
Water --17 <1
School --284 2
Sphere of Influence
Significant Ecological
Area
--3513 30
Note: The Golf Course and Community Core Overlay designations cover the same area.
Source: Dyett & Bhatia, 2019.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-17
2.0 LAND USE & ECONOMIC DEVELOPMENT
Table 2-3: Potential Planning Area Buildout by 2040
Existing (2016)Net New 2040 Total
Housing Units 18,910 3,750 22,670
Households 18,310 3,260 21,530
Population 57,900 8,800 66,700
Jobs 14,700 7,000 21,700
Note: Numbers may not add precisely due to rounding. Households are rounded to the nearest 10, and population and jobs are
rounded to the nearest 100.
Source: CA Department of Finance, 1/1/2015; Dyett and Bhatia, 2017; the 2015 Q2 California Employment Development
Department.
BUILDOUT
One purpose of the General
Plan is to ensure that the City
can accommodate the potential
population and job growth through
the Plan’s horizon year of 2040.
Policies in the General Plan will
allow the City to meet the needs
of the future residents and workers,
including housing for a diversity
of residents, parkland and public
facilities, and adequate options
for non-residential development to
provide employment opportunities
and retail and services that respond
to the community’s daily needs.
Potential new development
through the horizon year and the
corresponding growth in population
and employment is referred to
as “buildout.” Buildout is based
on existing development and an
estimated amount of potential
new development in the Planning
Area. Buildout estimates should
not be considered a prediction
for growth, as the actual amount
of development that will occur
through 2040 is based on many
factors outside of the City’s control,
including changes in regional
real estate and labor markets and
other long-term economic and
demographic trends. Therefore,
buildout estimates represent
potentialities rather than definitive
figures. To estimate buildout,
assumptions were made about the
density of development in each
proposed land use designation
as explained above, as well
as the percentage of parcels
that would actually develop
depending on location and land
use designation. The designation
of a site for a particular land use
in the General Plan does not
guarantee that the site will be
developed or redeveloped with
that use or assumed density during
the planning period, as future
development will rely primarily on
each property owner’s initiative.
Table 2-3 shows the potential
buildout of the General Plan
in terms of new development,
residents, and jobs. According to
projections, an estimated 3,200 new
households, 8,800 new residents,
and 7,000 new jobs could result
in the Planning Area under the
General Plan by 2040. It is expected
that much of this growth will occur
in the focus areas or as infill, while
most of the existing residential
neighborhoods will experience less
growth and change.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-18
GENERAL
GOALS
LU-G-1 Maintain a balanced mix of land uses,
including employment, residential, retail,
and open space, including open space
devoted to the preservation of natural
resources, to support a vibrant community
and Diamond Bar’s quality of life.
LU-G-2 Encourage compact growth and prioritize
infill development to preserve existing
large blocks of natural open space
within the City and Sphere of Influence
including Tonner Canyon and Tres
Hermanos Ranch; and enhance community
character, optimize city infrastructure
investments, provide pedestrian- and
bicycle-friendly neighborhoods,
and enhance economic vitality.
LU-G-3 In areas planned to accommodate new
growth, ensure quality design that
makes a positive contribution to
the character of Diamond Bar.
LU-G-4 Locate new residential growth in or adjacent
to mixed-use centers and transit stations
to support regional and statewide efforts
to encourage sustainable land use
planning and smart growth principles.
LU-G-5 Manage development in a manner consistent
with the capabilities of the City to provide
public services and facilities effectively.
POLICIES
LU-P-1 Ensure that the scale and massing of new
development provides sensitive transitions
or design techniques in building height,
bulk, and landscaping to minimize
impacts on adjacent, less intensive
uses, particularly residential uses.
G OALS & POLICIES
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT
2.0
2-19
G OALS & POLICIES
LU-P-2 Allow clustering or transferring of all or part of
the development potential of a site to a
portion of the site to protect significant
environmental resources such as vegetated
habitats, sensitive species, wildlife movement
corridors, water features, and geological
features within proposed developments as
open space if the developer takes action
to preserve the open space in perpetuity.
Preservation can occur through methods
including, but not limited to, dedication
to the City or a conservation entity such
as a conservancy, mitigation bank, or
trust, or through conservation easements,
deed restrictions, or other means.
LU-P-3 As opportunities arise, collaborate with
regional agencies and neighboring
jurisdictions on land use and transportation
planning in line with regional planning
efforts such as the Regional Transportation
Plan/Sustainable Communities Strategy.
LU-P-4 Monitor and evaluate potential impacts of
proposed adjacent, local, and regional
developments to anticipate and require
mitigation to the greatest extent feasible
to reduce land use, circulation, and
economic impacts on Diamond Bar.
LU-P-5 Ensure that adequate public services,
facilities, and infrastructure are
available or provided to support
new development, including water,
wastewater, stormwater, solid waste,
transportation, public safety, and parks.
LU-P-6 When appropriate, require new development
to pay its fair share of the public
facilities and off-site improvements
needed to serve the proposed use.
LU-P-7 As larger vacant or underutilized sites within
the built environment are developed
or redeveloped, maximize multimodal
accessibility with appropriately designed
street networks, and walkable block
sizes scaled to proposed uses.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-20
RESIDENTIAL
GOALS
LU-G-6 Preserve existing residential neighborhoods to
retain the qualities Diamond Bar residents love,
such as easy access to preserved natural open
spaces, while supporting and encouraging
well-designed, complete neighborhoods with
safe streets, access to shopping and services,
and community parks and gathering places.
LU-G-7 Promote a variety of housing and
neighborhood types that respond
to a range of income, household
sizes, and accessibility levels.
POLICIES
LU-P-8 Ensure that new residential development be
compatible with the prevailing character
of the surrounding neighborhood in terms
of building scale, density, massing, and
design. Where the General Plan designates
higher densities, provide adequate
transitions to existing development.
LU-P-9 Incorporate architectural and landscape
design features in new development
that create more pedestrian-friendly
neighborhoods, such as orientation to the
street; set-back, or detached garages;
tree-lined streets; and landscaped
parkways between streets and sidewalks.
LU-P-10 Provide opportunities for and incentivize the
development of housing types that are
affordable to all segments of the Diamond
Bar community, including senior housing
and independent assisted living facilities,
residential care facilities, and rental and
for-sale housing units affordable to low-
and moderate-income households.
LU-P-11 Maintain a system of identifiable,
complementary neighborhoods, providing
neighborhood identity signage where
appropriate and ensuring that such
signage is well maintained over time.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT
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G OALS & POLICIES
COMMERCIAL, OFFICE, AND INDUSTRIAL
GOALS
LU-G-8 Promote the development of distinct, well-
designed commercial centers that serve
neighborhood residents, community
members, and/or the region at large
and help maintain economic vitality.
LU-G-9 Provide for the concentration of office and
commercial uses near regional access
routes, transit stations, and existing and
proposed employment centers.
LU-G-10 Support the long-term viability of existing
commercial, office, and light industrial
uses, designated for continued
use in the General Plan.
LU-G-11 Support existing commercial centers by
encouraging ongoing investment and, where
appropriate, reuse and redevelopment.
POLICIES
LU-P-12 Ensure that commercial uses and shopping
centers are designed in a manner compatible
with adjacent residential areas in terms of
traffic and noise impacts, building scale,
and appropriate transitions and buffers.
LU-P-13 Promote the revitalization of existing
neighborhood commercial centers by
encouraging property owners to maintain
and improve the appearance of individual
buildings and commercial centers through
building façade improvements, landscaping,
and pedestrian improvements.
LU-P-14 Improve vehicular accessibility, traffic flow,
and parking availability as well as pedestrian
and bicycle access and amenities within
office, commercial, and industrial areas.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-22
MIXED USE
See Chapter 3: Community Character and Placemaking
for additional policies regarding the form and design of
development in the mixed-use focus areas.
GOALS
General
LU-G-12 Encourage compact mixed-use
developments and projects that are
walkable, designed to encourage
community interaction, and fulfill a
diversity of local commercial, employment,
housing, and recreational needs.
LU-G-13 Maximize multi-modal accessibility to and
connectivity within mixed-use areas.
LU-G-14 Foster development of nodes or clusters of
mixed-use centers to promote city and
neighborhood identity, improve accessibility
to stores, parks, natural open spaces, and
services, and promote walkable, pedestrian-
scaled retail and dining destinations.
Neighborhood Mixed Use
LU-G-15 Promote the development of a vibrant
corridor with a mix of uses, including
residential uses and neighborhood-serving
services and amenities, such as parks
and open spaces that fulfill a diversity
of local needs within walking and biking
distance of neighborhood residents.
LU-G-16 Create a well-designed, pedestrian-friendly,
mixed-use neighborhood that encourages
community interaction and healthy lifestyles
while reducing reliance on automobiles.
LU-G-17 Ensure that new development is sensitive to
the scale of adjacent residential uses,
while allowing for higher intensity
development along Diamond Bar Boulevard
to foster the corridor’s revitalization.
LU-G-18 Encourage a diversity of housing
types and products.
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G OALS & POLICIES
Transit-Oriented Mixed Use
LU-G-19 Leverage the proximity of the City of Industry
Metrolink station and Foothill Transit
facility to create an engaging, compact,
mixed-use neighborhood that encourages
multi-modal transportation and responds
to a diversity of housing needs.
LU-G-20 Ensure the adequate provision of spaces for
recreation, community gathering, amenities,
programming, and services that can adapt
to fulfill the demographic needs of residents
consistent with the Diamond Bar parkland
standard (5 acres per 1,000 residents) and
the Parks and Recreation Master Plan.
LU-G-21 Ensure that new development is sensitive to
the scale, density, and massing of
adjacent residential uses and potential
sources of noise and air pollution.
Town Center Mixed Use
LU-G-22 Promote and support the commercial area on
both sides of Diamond Bar Boulevard
from Golden Springs Drive to SR-60 as a
vibrant, pedestrian-oriented Town Center
that serves as Diamond Bar’s primary
specialty retail and dining destination and
is accessible to all Diamond Bar residents.
LU-G-23 Ensure an inviting and comfortable public
realm to encourage pedestrian
activity in the Town Center area.
LU-G-24 Allow residential and office uses as secondary
to commercial (retail, dining,
and entertainment) uses.
Community Core Overlay
LU-G-25 Support continued operation of the Diamond
Bar Golf Course by Los Angeles
County as a public amenity.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-24
LU-G-26 Should Los Angeles County choose to cease
operations of the Diamond Bar Golf Course or
reduce the area of the Golf Course, promote
development of the portion of the Golf
Course north of Grand Avenue predominantly
as a public park/consolidated golf course
with additional community or civic uses,
and the portion south of Grand Avenue
as a walkable mixed-use community and
regional destination offering retail, dining, and
entertainment uses; plazas and community
gathering spaces; supporting residential
uses; and civic and other supporting uses.
POLICIES
General
LU-P-15 Encourage mixed-use development in infill
areas by providing incentives such as
reduced parking requirements and/
or opportunities for shared parking.
LU-P-16 In residential mixed-use areas, encourage the
clustering of non-residential uses
at key visible locations.
LU-P-17 Promote site designs that create active street
frontages and introduce pedestrian-scaled
street networks and street designs.
LU-P-18 Development should be sensitive to the
building form, density, massing, and scale
of surrounding residential neighborhoods.
LU-P-19 To meet the recreational needs of new
residents, ensure that new residential and
mixed-use developments larger than four
acres incorporate public parkland in the
neighborhoods where such developments
are located. Residential and mixed-use
developments under four acres may
provide dedicated parkland, in lieu fees,
or a combination, in accordance with
Diamond Bar’s park acreage standards.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT
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G OALS & POLICIES
LU-P-20 Encourage the consolidation and location of
parking to the rear or side of buildings.
Neighborhood Mixed Use
LU-P-21 Promote clusters of mixed-use commercial
development along Diamond Bar
Boulevard to provide neighborhood-serving
commercial uses and neighborhood parks
within walking distance of residences by:
a. Requiring development at the north and
south ends of the corridor (within
1,000 feet of the two ends, as feasible,
taking into account site topography)
to provide commercial development
along the majority of the frontage
along Diamond Bar Boulevard; and
b. Allowing development elsewhere along
the corridor to provide commercial uses.
LU-P-22 Encourage commercial development to
incorporate outdoor green
spaces appropriate and usable
for patrons and visitors.
LU-P-23 Residential and mixed-use developments on
sites larger than two acres should
include a range of housing types
that meet the needs of a diversity of
income levels and household sizes.
LU-P-24 Buildings located along corridors should be
designed to face the street and define
the public realm with a mix of building
patterns, ground floor transparency
for commercial uses, and pedestrian-
oriented elements such as building
entrances and public outdoor spaces.
LU-P-25 Promote neighborhood interaction by
providing landscaped walkways,
bikeways, and public spaces such as
parks and commercial plazas, etc.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-26
LU-P-26 Maximize multi-modal (transit, automobile,
cycling, and pedestrian) connections to
other destinations in Diamond Bar, such as
schools, parks, job centers, and community
gathering spaces like the Town Center by:
a. Filling gaps in and expanding and/or
upgrading the bikeway network to ensure
safe and efficient bicycle mobility. Gaps
that could be addressed in this area
include the northern ends of Diamond
Bar Boulevard and Golden Springs Drive.
b. Improving pedestrian comfort and safety
by implementing traffic calming measures
on Diamond Bar Boulevard between
Temple Avenue and Sunset Crossing
Road, providing shading through the
addition of street trees along Diamond
Bar Boulevard and Sunset Crossing
Road, and encouraging pedestrian-
oriented elements on buildings and street
furniture on Diamond Bar Boulevard.
Transit-Oriented Mixed Use
LU-P-27 To promote a healthy jobs/housing balance,
each new development should include
a minimum nonresidential FAR of .25.
LU-P-28 Encourage development of live-work spaces.
LU-P-29 Allow high-density housing at a minimum
density of 20 units per acre and up to a
maximum of 30 units per acre, with a non-
residential FAR of up to 1.5 to promote a
compact development pattern that reflects
the area’s proximity to transit. Allow supporting
commercial uses along Brea Canyon Road.
LU-P-30 Ensure that building frontages and
streetscaping define the public realm and
encourage pedestrian activity and comfort
with a mix of building patterns, ground floor
transparency for commercial uses, and
pedestrian-oriented elements such as building
entrances and public outdoor spaces.
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G OALS & POLICIES
LU-P-31 Promote convenient, attractive, and safe
pedestrian, bicycle, and transit
connections between the Transit-
Oriented Mixed Use neighborhood and
surrounding neighborhoods and other
destinations within Diamond Bar such as
schools, the Town Center, and parks.
LU-P-32 In conjunction with new development,
implement an overall parking strategy
for the Transit-Oriented Mixed Use
neighborhood, including consolidation
of smaller parking lots and district-wide
management of parking resources.
LU-P-33 Consider amendments to the Development
Code parking regulations as needed to allow
lower parking minimums for developments
with a mix of uses with different peak
parking needs, as well as developments
that implement enforceable residential
parking demand reduction measures, such
as parking permit and car share programs.
LU-P-34 Ensure that development evaluates and
mitigates to extent practical noise
and air quality issues related to the
proximity of the SR-60 and Metrolink.
Town Center Mixed Use
LU-P-35 Ensure that any reuse, redevelopment, or
refurbishment of the Town Center area
maintains a dominance of retail, dining,
and entertainment uses. Allow residential
uses within the designation’s permitted
maximum range, as well as offices, either
on upper floors or otherwise in locations
that do not detract from the area’s
predominant role as a community shopping,
dining, and entertainment destination.
LU-P-36 Prioritize and support renovation, infill, and
reuse of the existing commercial center.
Require, where appropriate, redesign
and modernization of architectural
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-28
treatment and the introduction of finer-
grained pedestrian network, as well
as utilization of parking lots to create
central gathering spaces and make the
Town Center more pedestrian-friendly.
LU-P-37 Utilize buildings and streetscapes to define
the public realm and encourage pedestrian
activity and comfort.
To further promote these objectives,
incorporate attractive landscaping
elements and usable outdoor
green spaces, and discourage
new drive through uses.
LU-P-38 Promote site designs that create an active
street frontage and screen off-street
parking from the Diamond Bar Boulevard
and Golden Springs Drive frontages.
LU-P-39 Streetscape and intersection improvements
along the major corridors of South Diamond
Bar Boulevard and Golden Springs Drive
should enhance connectivity, comfort, and
safety for all modes of travel, and increase
accessibility to and from surrounding areas.
LU-P-40 Study, as necessary, the implementation of
safe pedestrian connectivity between
the north and south sections of the
Town Center Mixed-Use project site
and at Lorbeer Middle School.
Potential strategies for achieving safe
pedestrian connectivity may include
traffic calming measures along
the roadways, crosswalk visibility
improvements, ensuring adequate
time for walk signals, refuge islands,
bulb-outs, bridges, and others.
LU-P-41 Maximize accessibility for transit,
automobiles, cyclists, and pedestrians
to the Town Center from surrounding
neighborhoods, the Metrolink station,
and other Diamond Bar destinations.
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G OALS & POLICIES
LU-P-42 Avoid expanses of surface parking and
encourage the consolidation and
location of parking to the rear or side
of buildings where appropriate.
LU-P-43 When updating the Development Code’s
parking standards or preparing specific
plans, evaluate parking ratios for the
Town Center to balance the financial
feasibility of development projects with the
provision of adequate parking for visitors.
Coordinate with developers and transit
agencies to the extent possible to provide
alternative modes of transportation to
allow for reduced parking requirements.
LU-P-44 When warranted, a feasibility study should be
prepared for any hotels proposed in the
Town Center area to demonstrate market
demand and economic viability.
Community Core Overlay
LU-P-45 Prepare a master plan or specific plan for any
future development within the Community
Core overlay area that creates a mixed-
use, pedestrian-oriented community and
regional destination. Approximately 100
acres north of Grand Avenue is to support
a park or consolidated golf course along
with additional community or civic uses.
The southern portion is to accommodate
a mix of uses emphasizing destination and
specialty retail, dining, and entertainment,
including opportunities for residential,
hospitality, and community and civic uses.
LU-P-46 Where appropriate, require development to
provide courtyards and plazas, public
art, and landscaped open spaces and
pathways between buildings that promote
safe and convenient pedestrian movement.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-30
LU-P-47 Buildings should be designed to define the
public realm and promote sidewalk
activity and neighborhood
interaction in public spaces.
LU-P-48 Create a fine-grained (shorter blocks),
pedestrian-scaled street network, and
require buildings and streetscapes to
encourage pedestrian activity and comfort.
LU-P-49 Promote convenient, attractive, and safe
pedestrian, bicycle, and transit connections
both within the Community Core area
and between the Community Core and
surrounding neighborhoods and other
destinations within Diamond Bar.
LU-P-50 Where practicable, consolidate and locate
parking in a manner that encourages
pedestrian activity. Avoid expanses of
surface parking (see Chapter 3, Community
Character and Placemaking).
LU-P-51 Provide streetscape and intersection
improvements along Golden Springs Drive
to enhance comfort and safety for all
modes of travel and increase accessibility
to and from surrounding areas.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT
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G OALS & POLICIES
PUBLIC FACILITIES, OPEN SPACE, AND HILLSIDES
See Chapter 6: Public Facilities and Services for additional
policies regarding the provision of parks and public
facilities. See Chapter 5: Resource Conservation for
additional policies regarding hillside conservation and
open space preservation.
GOALS
LU-G-27 Designate adequate land throughout the
community for educational, cultural,
recreational, and public service activities to
meet the needs of Diamond Bar residents.
LU-G-28 Preserve open space, ridgelines, and hillsides
to protect the visual character of
the city, provide for public outdoor
recreation, conserve natural resources,
support groundwater recharge,
protect existing and planned wildlife
corridors, and ensure public safety.
For the purposes of this goal, open space is
defined as any parcel or area of land
or water that is essentially unimproved
and devoted to open space use, which
may include the preservation of natural
resources, the managed production
of resources, outdoor recreation, the
protection of public health and safety,
support for the mission of military
installations, or the protection of tribal
cultural resources (California Government
Code Sections 51075 and 65560).
Unimproved land that is designated for
other uses is considered vacant land rather
than open space but may become open
space if it is dedicated, acquired by a
public entity, or otherwise preserved in
perpetuity. Dedicated open spaces are
designated on the Land Use Diagram with
the Open Space land use classification.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-32
POLICIES
LU-P-52 When opportunities arise, collaborate with
public service providers and agencies
including, but not limited to, the Los Angeles
County Department of Parks and Recreation,
Walnut Valley and Pomona school districts,
Los Angeles County Sheriff’s Department,
Los Angeles County Fire Department, and
Walnut Valley Water District to designate
and pursue acquisition of land for public
facilities as necessary to serve unmet
facility needs of Diamond Bar residents.
LU-P-53 Ensure adequate parkland to serve the
recreational needs of Diamond Bar residents
by providing for a range of park sizes and
amenities, equitably distributed throughout
the city. Where necessary to adequately
expand the park system and/or provide
specialized recreational facilities and
programming as identified in the Parks and
Recreation Master Plan, actively pursue
the acquisition of additional parkland.
LU-P-54 When a public agency determines that land
it owns is no longer needed, advocate for the
property to first be offered to other agencies,
including the City of Diamond Bar, for public
uses, prior to conversion to private sector use.
LU-P-55 Preserve publicly-owned, undeveloped
hillsides, as well as privately-owned
hillsides with an Open Space General
Plan designation, as natural open space
in perpetuity. On privately-owned
property which has a residential land use
designation, preserve hillsides as natural
open space through Diamond Bar’s Hillside
Management Ordinance by allowing
residential development only at the
permitted densities and where development
would not detract from the protection and
overall perception of the hillsides as natural
topographic and ecological features, or
negatively impact public safety or welfare.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT
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G OALS & POLICIES
LU-P-56 Ensure that development on privately-
owned, residentially designated land
in hillside areas is compatible with
surrounding natural areas promoting
the following design principles:
a. Minimize—as articulated by the
landform grading criteria of the
Development Code’s Hillside
Management regulations—excavation,
grading, and earthwork to retain
natural vegetation and topography;
b. Preserve existing vistas of significant
hillside features such as ridgelines,
particularly from public places;
c. Do not create unsafe conditions;
d. Incorporate site and architectural
designs that are sensitive to
natural contours and land forms
and hydrological features;
e. Preserve natural watersheds, including
existing vegetation within undeveloped
hillside areas to the maximum
extent feasible, including mature
trees and native plant materials;
f. Incorporate fuel modification as part of
the Fire Department’s approved
fuel modification program;
g. Utilize planting palettes consisting of
drought tolerant, fire resistant,
non-invasive plants that are native
to or compatible with those in
the surrounding area; and
h. Group plants within swale areas to more
closely reflect natural conditions
within landform graded slopes.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-34
2.3 ECONOMIC DEVELOPMENT
POPULATION AND EMPLOYMENT TRENDS
Population
Between the 1990 U.S. Census and
the 2016 California Department of
Finance population projection, the
city gained approximately 3,400
residents, as shown in Table 2-4.
This represents an annual growth
rate of only 0.2 percent a year over
a 26-year period. Since 1990, the
city’s overall population growth has
not kept pace with the region or
county’s growth due to the fact that
the city is largely built out and there
have been limited opportunities for
housing development.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-35
2.0 LAND USE & ECONOMIC DEVELOPMENT
Geography 4/1/90 1 4/1/00 1 4/1/101 1/1/16 2
Diamond Bar 53,672 56,287 55,544 57,081
Region3 447,367 557,497 580,083 608,952
Los Angeles
County
8,863,052 9,519,330 9,818,605 10,241,335
State Total 29,758,213 33,873,086 37,253,956 39,255,883
Annual Growth
(by Period)
1990 -2000 2000-2010 2010 - 2016 1990 - 2016
Diamond Bar 262 (74) 256 131
Region 11,013 2,259 4,812 6,215
Los Angeles
County
65,628 29,928 70,455 53,011
State Total 411,487 338,087 333,655 365,295
Percent Growth
by Period
1990 -2000 2000-2010 2010 - 2016 1990 - 2016
Diamond Bar 0.5%-0.1%0.3%0.2%
Region 2.2%0.4%0.5%1.2%
Los Angeles
County
0.7%0.3%0.4%0.6%
State Total 1.3%1.0%0.5%1.1%
Notes:
1. US Census population counts from April 1 in 1990, 2000, and 2010
2. California Department of Finance Estimate from January 1, 2016. Note that this figure differs slightly from the City’s 2016
population estimate presented in Table 2-3 of this General Plan, which was derived based on existing land use.
3. Region: Brea, Chino, Chino Hills, Covina, Diamond Bar, Industry, Pomona, Walnut, and West Covina
Source: California Department of Finance; US Census
Table 2-4: Population Trends 1990 - 2016
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-36
Ethnic Composition
Diamond Bar has an increasingly
diverse population. While changing
demographics do not necessarily
affect land use decisions, different
cultures tend to have different
preferences and priorities, and may
change the market orientation of
some residential and non-residential
land uses. As such, it is important
to consider how the projected
ethnic composition of the city’s
population might impact future
land use decisions. The city’s Asian
population composition is largely
second-generation residents and
comparable to mature ethnic cities
such as Cerritos or Irvine, where the
population speaks English very well.
Ethnic diversity is an attribute that
may shape specific commercial
and residential preferences.
Age
The city’s population is aging, and
the senior population’s growth
and transition into retirement will
provide unique challenges for the
city. The market created from this
demographic shift might require
changes in the city’s housing
stock to provide opportunities
for residents to age in place.
Alternatively, changes in their
housing preferences could create
opportunities for younger families
wanting to move into the city.
Employment Base
Since the Great Recession (2007
to 2009), the combination of
lost jobs and decreased labor
force participation has kept
unemployment low in the city.
Over time, this could become a
concern if the city’s labor force
participation does not increase and
the number of resident jobs does
not return to pre-recession levels.
New employment opportunities
are critical to meet the need to
increase the city’s employment
base for residents and non-residents
alike.
The city has many positive attributes
relating to employment. First, there
has been a greater concentration
of higher paying jobs in the city
compared to Los Angeles County.
Second, commuter directional
analysis (OnTheMap [US Census
Bureau, Center for Economic
Studies], 2014) suggests that
because of the city’s connection
to multiple freeway networks, there
is a relatively equal distribution of
employees commuting from various
areas in the region. Finally, the city
has many business-friendly policies
to attract future job growth. Future
commercial development and
the absorption of existing vacant
commercial space represent
potential opportunities for future
employment-serving land uses.
Employment Sectors
The largest percentage of Diamond
Bar residents are employed in the
Administration & Support - Waste
Management and Remediation
sector, followed by Finance and
Insurance, and Education sectors
(as illustrated in Figure 2-3).
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-37
2.0 LAND USE & ECONOMIC DEVELOPMENT
In 2015, the top employers in Diamond Bar, as shown in Figure 2-4, were
the Walnut Valley Unified School Districts, the South Coast Air Quality
Management District, and various private finance and insurance
providers.
Figure 2-3: Jobs in the Top 15 Industry Sectors (2015)
Figure 2-4: Top Employers (2015)
Source: Labor Market Information, Info USA, City Manager’s Office
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-38
FUTURE POPULATION AND EMPLOYMENT GROWTH
The Southern California Association
of Governments (SCAG) has
projected that the city will grow at
a slower pace than experienced
prior to its incorporation in 1989.
Between 2016 and 2040, the City
projects Diamond Bar’s population
will grow to 66,700 residents,
translating to a 0.6-percent annual
growth rate over the next 20
years. Figure 2-5 shows population
projections for the city through
2040.
Figure 2-5: Diamond Bar Population Growth, 1990 - 2040
Source: U.S.Census 1990, 2000, and2010; CaliforniaDOF, 2018; Dyett&Bhatia, 2019.
Given the land use changes and
policies proposed in this Plan
as well as regional employment
projections, the City projects strong
overall job growth in Diamond
Bar over the next 20 years, with
projected employment increasing
by nearly 48 percent from 14,700
jobs in 2016 to 21,700 jobs in
2040. Table 2-5 shows projected
employment growth totals and
by land use. In order for the City
to capitalize on this employment
market, it will need to maintain a
positive climate for business growth
and retention, and ensure land
availability in appropriate locations.
Diamond Bar General Plan 2040 | LAND USE & ECONOMIC DEVELOPMENT 2-39
2.0 LAND USE & ECONOMIC DEVELOPMENT
Non-
Residential
Land Use
Category
2016
Estimated
Total Jobs
Percent of
Total
2040
Projected
Total Jobs
Percent
of Total
Estimated
Change in
Jobs, 2016-
2040
Retail 3,100 10%3,100 14%1,600
Office 7,300 50%11,400 53%4,100
Industrial 2,100 14%1,700 8%(400)
Other
Commercial1
3,800 26%5,500 25%1,700
Total 2 14,700 100%21,700 100%7,000
Notes:
1. Other commercial uses include accommodation and food services and other miscellaneous services (excluding public
administration).
2. Totals may not add due to rounding.
Source: Dyett & Bhatia, 2019.
Table 2-5: Projected Employment Growth by Non-
Residential Land Use Category, 2016-2040
Source: Board of Equalization and Department of Finance, 2014.
Figure 2-6: Historic Per Capita Retail Spending (2005 - 2014)
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-40
FISCAL SUSTAINABILITY
Diamond Bar is largely built out,
resulting in slow growth projections
for both population and housing
(see Existing Conditions Report –
Volume II: Economic Review and
Market Assessment prepared for
the General Plan Update). As a
result, and in order to address
future fiscal sustainability concerns,
new development will be needed
in order to grow the city’s base
of residents and employment
opportunities, as well as increase its
market capture with a more diverse
retail environment.
Different land use changes can
have different fiscal impacts on the
City’s General Fund. For example:
• Residential land uses typically
have the highest cost of service
and generates the lowest
revenue resulting in a negative
fiscal impact.
• The development of industrial
and office space in the city
will likely have a positive fiscal
impact, as jobs created by
these land uses would typically
require fewer city services
than residential development.
An increase in employment
opportunities could also attract
new residents to the city or allow
current residents to work closer
to home rather than commuting.
• New retail development can
have a positive impact on
the General Fund through the
generation of sales tax.
• Hotel and other hospitality land
uses typically have high net
positive fiscal impacts because,
like other commercial uses, the
service costs are lower than
residential uses, and the city
receives the full voter-approved
transient occupancy tax rate.
Unlike other cities in the region
and Los Angeles County as a
whole, Diamond Bar’s per capita
retail spending has not grown
since 2005, as shown in Figure 2-6.
The decrease in the per capita
generation of sales tax revenues
would indicate that the city’s retail
base has not grown sufficiently to
maintain its capture rate. For the
city to remain economically viable
over the long-term it should strive to
continue expanding its retail base
by creating a more diverse retail
environment to increase the market
capture from its higher income
households within the city and
others in the region. Attracting new
development as proposed in the
new mixed-use focus areas, as well
as supporting existing businesses to
increase their market capture within
the city, will be crucial in terms of
sustaining a diverse economy and
stable fiscal standing in Diamond
Bar.
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G OALS & POLICIES
ECONOMIC DEVELOPMENT
See Chapter 3: Community Character and Placemaking
for policies regarding creating a sense of place and
attractive public realms.
GOALS
ED-G-1 Prioritize infill development opportunities
and the reuse of existing vacant
commercial space to grow the city’s base
of residents and employment to ensure
long-term fiscal sustainability and promote
conservation of natural open space.
ED-G-2 Provide for the development of jobs and
commercial uses within Diamond
Bar to reduce residents’ commutes,
and to encourage residents to
shop and dine locally.
ED-G-3 Support the retention, rehabilitation, and/or
expansion of existing businesses, and
the attraction of new businesses.
ED-G-4 Promote development of flexible
workspaces that are adaptable over
time to changing economic needs;
support co-working and start-up/
incubator business spaces.
ED-G-5 Support the use of Metrolink and local
transit connections as a means for non-
residents to commute to employment
opportunities in Diamond Bar.
ED-G-6 Facilitate the development of a labor force
with skills to meet the needs of the area’s
current and future businesses and industries.
ED-G-7 Monitor and regularly evaluate economic
conditions and economic
development goals.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-42
POLICIES
Commercial Centers
ED-P-1 Identify retail and service needs that are not
being met in the community, and
encourage the development or
redevelopment of commercial
centers to meet existing and future
demand for such services.
ED-P-2 Promote the visibility of commercial centers
from the freeway, where appropriate.
Efforts may include incorporation of
monument signage in Diamond Bar
visible from the freeway, and/or
wayfinding signage guiding the public
to key places throughout the City.
ED-P-3 Create commercial centers or districts that
have a sense of place and provide
attractive places to shop, dine, and
gather. Within these areas, support
the development of uses and distinct
characters that complement other
commercial areas within Diamond
Bar and adjacent jurisdictions.
ED-P-4 Collaborate with business owners, the
Regional Chamber of Commerce - San
Gabriel Valley and/or business development
organizations to promote shopping and
dining opportunities in Diamond Bar.
Efforts may include listing information on
local business on the City’s website,
working with the Regional Chamber or
business development organizations to
establish and sustain promotional events
and programs, increasing local business
participation at community events, and
developing promotional materials and
guides to showcase existing businesses
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G OALS & POLICIES
ED-P-5 Work with existing commercial center
owners and commercial real estate
professionals to enhance commercial
development opportunities that meet
the needs of adjacent neighborhoods
and other nearby uses by facilitating
communication between developers and
target populations, identifying additional
development or redevelopment sites in and
around the centers, and improving exposure
along adjacent transportation corridors.
Community-Serving Uses
ED-P-6 Work with property owners of existing office
centers to increase the daytime
population and facilitate opportunities
to attract quality office tenants and
supporting commercial businesses.
ED-P-7 Allow for home occupations where
compatible with the privacy and residential
character of the neighborhood.
ED-P-8 Encourage provision of common or rentable
workspaces that can be used by
residents for efficient work-from-home
use to be incorporated into attached
residential development projects,
ED-P-9 Promote the use of multi-modal connections
to serve commercial and office uses within
Diamond Bar, thereby enhancing transit,
ride-sharing, pedestrian, and bicycle
infrastructure opportunities, and reducing
automobile congestion within the City.
LAND USE & ECONOMIC DEVELOPMENT | Diamond Bar General Plan 20402-44
City Programs and Partnerships
ED-P-10 Facilitate access to City and regional
services, incentives, and public-private
partnership opportunities available to
property owners and businesses seeking to
perform façade or structural improvements,
expand operations, or provide incubation
spaces for startup businesses.
ED-P-11 Facilitate partnerships between area
businesses and educational and training
institutions, such as the Walnut Valley and
Pomona Unified School Districts, Cal Poly
Pomona, Cal State Fullerton and Mt. San
Antonio Community College, to provide
training programs that will enable the labor
force to meet the needs of business and
prepare for emerging job opportunities.
ED-P-12 Partner with the Diamond Bar Public Library
and/or business mentorship programs
to offer computer literacy, job search,
and personal and business development
training workshops that are accessible
to residents of all income levels.
ED-P-13 Periodically update the City’s Economic
Development Action Plan to evaluate
citywide economic conditions and to
reflect new trends such as emerging
industries and new market opportunities.
The Community Character
and Placemaking Chapter
guides the form and character
of future development in
Diamond Bar. It provides
strategies to strengthen the
city’s identity through design
and enhance the character of
the community by defining the
spatial relationships between
the city’s various gateways,
neighborhoods, and centers of
activity.
COMMUNITY
CHARACTER &
PLACEMAKING 3.0
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-2
3.1 INTRODUCTION
This chapter outlines the desired
character of the mixed-use focus
areas and provides direction to
ensure that new development is
context sensitive. Thus, it provides
policy direction at a citywide
scale, as well as a framework for
development occurring in the
Town Center, Neighborhood Mixed
Use, Transit-Oriented Mixed Use,
and Community Core focus areas.
The Community Character and
Placemaking Chapter consists of
narrative, goals and policies, as
well as diagrams illustrating the key
redevelopment opportunities in
Diamond Bar. Policy text and maps
should be considered collectively
as project approvals or future
amendments are made.
RELATIONSHIP TO STATE LAW
While the inclusion of community
design is not required as a
mandated element of a general
plan, California Government Code
Section 65303 states that a general
plan may include additional
elements that a community
considers important to the physical
development of the city. All
elements, whether mandatory
or optional, are required to be
consistent with one another.
RELATIONSHIP TO OTHER ELEMENTS
This chapter is closely related
to Chapter 2, Land Use and
Economic Development and
Chapter 4, Circulation. The Land
Use and Economic Development
Chapter lays out the land uses
and development densities and
intensities for new development,
as well as basic policies related
to building scales, while the
Circulation Chapter provides
direction on connectivity and
access for different modes of
travel within and around new
development and the city as a
whole.
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COMMUNITY CHARACTER & PLACEMAKING
3.2 CITYWIDE CHARACTER AND DESIGN
In 2019, Diamond Bar remains
primarily a residential community
of quiet neighborhoods with
commercial and office uses limited
to small auto-oriented clusters
concentrated around intersections
of major arterials. Shopping centers
and office parks are suburban in
character; they are designed to
be accessed via car, with buildings
set far back from roadways and
facing towards large parking lots
rather than streets. While these
commercial centers serve the daily
needs of Diamond Bar residents,
their auto-oriented design and the
low diversity of uses does not allow
them to act as true destinations or
centers of civic life.
Residents of Diamond Bar value
the existing community character
of the City, including its family-
friendly neighborhoods and its
country-living feel, enhanced by
open spaces and hillside views.
According to community members,
elements that would strengthen the
character of Diamond Bar include
the addition of a more traditional
downtown or town center for retail,
gathering, and entertainment
purposes; the revitalization of
aging commercial centers; and a
continued focus on high quality
design and beautification.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-4
URBAN DESIGN FRAMEWORK
As outlined in Chapter 2, Land Use
and Economic Development, four
focus areas have been identified
that could accommodate
future mixed-use development
opportunities (see also Figure 3-1:
Urban Design Framework). These
mixed-used development areas are
intended to complement existing
residential neighborhoods and
commercial centers, providing
places where residents and
visitors can live, work, and play.
These focus areas are envisioned
as attractive, memorable
places in the community, with
a pedestrian orientation and a
mix of complementary uses. The
Town Center Mixed-Use area will
establish a new center of civic
life in Diamond Bar, responding
to the community’s desire for a
more traditional “downtown,” with
buildings and streets designed to
promote walkability accompanied
by spaces for dining and gathering,
while the other focus areas are
envisioned as community- or
neighborhood-scaled. These focus
areas are discussed in further detail
below in Section 3.3: Focus Areas.
By building on the city’s
existing assets and planning
new, appropriately-designed
development within the General
Plan’s policy framework, it is
envisioned that Diamond Bar will
become a more livable community,
with a strong sense of place and
improved quality of life for its
current and future residents.
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING 3-5
Figure 3-1 Urban Design Framework
Union Pacic RailroadSouthernPacificRailroadRiverside Metrolink LineGRA
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GATE W AYC O P LEYDRDIAMOND BAR BLVDBREACANYONRDD IA M O N D B A RBLVDG O LD EN S P R ING S D RLEMON
AVELYCOMING ST BREACA
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60
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MetrolinkStation
Focus Area
Existing Commercial Center
Parks/Open Space
0 1 2
MILES
1/21/4
Boulevards
City Limits
Sphere of Inuence
City Gateway
Focus Area Gateway
3.1 Urban Design Framework
PATHFINDER RD
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-6
CITY IDENTITY
Diamond Bar is defined by the
quiet, suburban nature of existing
residential development and its
backdrop of natural resources
and views, and is supported by
conscious efforts at placemaking.
Placemaking elements include
gateway monuments and
treatments that define entryways
into the city, public art installations
and artistic streetscape elements
that contribute to memorable
places and a unified character,
as well as landscaping, which
provides beauty in the public realm
while contributing to stormwater
management. Throughout the
city, existing placemaking efforts
and iconography tell the story of
Diamond Bar’s origins as a ranch.
Symbols of the city’s history—
including the Windmill (its oldest
landmark), native landscaping,
diamond-patterned pedestrian
crossings, and ranch-style
decorative features in the public
realm—connect modern-day
residents to their community’s roots.
This section explores the ways in
which Diamond Bar can strengthen
its identity as it continues to develop
and grow.
Gateways
Gateways are urban design elements
that mark the arrival or transition from
one place to another. Gateways add
to an area’s identity and sense of
place, while also serving as wayfinding
elements that help individuals navigate
locations they may not be familiar with,
facilitating access to key destinations.
Key features of effective gateways
include visual and directional cues, such
as:
• Gateway and wayfinding signage;
• Unified landscaping, including street
trees and plantings as well as planted
medians;
• Streetscape treatments such as
enhanced paving, street furniture,
and accent lighting;
• Prominent architecture at gateways
and key intersections; and
• Integration of private signage into the
gateway palette.
Diamond Bar has several existing
gateway monuments. The city’s border
with Chino Hills near the intersection
of Longview Drive and Grand Avenue
is marked with a grand entry sign
welcoming visitors to Diamond Bar. A
city entry landmark, featuring cattle
sculptures and a stylized recreation
of the original Diamond Bar Ranch
gateway, is located at Diamond
Canyon Park, near the intersection
of Diamond Bar Boulevard and Brea
Canyon Road. These features are part
of a unified streetscape design theme
intended to be established throughout
Diamond Bar. Other city entry points are
currently marked with older monument
features, which will be replaced over
time with structures that follow the
current streetscape theme and palette.
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COMMUNITY CHARACTER & PLACEMAKING
In addition to the gateways
announcing one’s arrival to the
Diamond Bar, the City may consider
additional gateways at entrances to
new mixed-use areas, including the
Town Center, Transit-Oriented Mixed
Use, Neighborhood Mixed Use, and
Community Core Overlay areas
shown in Figure 3-1: Urban Design
Framework.
Public Art
Public art plays an important role in
relating the story and identity of a
city, and in creating the opportunity
for residents and visitors to
participate and share in articulating
its identity. Diamond Bar residents
have expressed a desire to use
public art as a means to showcase
Diamond Bar’s rural beginnings and
evolving cultural diversity.
Encouraging public art supports
the growth of historical and cultural
awareness in the city. In particular,
public art within major activity
nodes and regional destinations
and along major pedestrian
corridors will play a key role in
showcasing the city’s identity.
Additional support from the City
may include the provision of
spaces, programs and facilities that
provide opportunities for artistic
and cultural engagement, as is
discussed in Chapter 8, Community
Health and Sustainability
Landscaping
Landscaping can contribute
greatly to placemaking and city
identity, while also playing a role
in environmental sustainability and
stewardship through measures
such as stormwater management,
carbon sequestration, and the
provision of habitats for wildlife. The
establishment of a landscaping
palette and corresponding
strategies can serve these myriad
purposes. Important factors to be
considered in the establishment
of a citywide landscaping palette
include the incorporation of
native, drought-tolerant plants,
the incorporation of colorful,
flowering plants, and stormwater
management opportunities.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-8
THE PUBLIC REALM
Streetscape
Streets are a foundational aspect of
community life, providing spaces for
community members to encounter
not only the various locations and
features of their city, but also one
another. Pleasant streetscapes—
which include site-specific building
frontages, sidewalks, street furniture,
and landscaping—create safe,
attractive, and active streets.
Streetscapes are also central to the
flow of people through an area,
and that area’s connection to the
city at large, as discussed further in
Chapter 4, Circulation.
As of 2019, streets within the City
are generally auto-oriented in
their design and function. As new
development occurs throughout the
city, there are several challenges
and opportunities for improved
street design. As discussed in the
Circulation Chapter, there are
opportunities to design streets in
that allow for safer transportation
for all modes, including walking
and bicycling. A major challenge
in terms of streetscapes is that
the character of the streets and
sidewalks that delineate the public
realm is often diminished by a weak
building-to-street relationship with
buildings oriented away from the
street or set back from roadways,
or the presence of fences blocking
views of buildings from the sidewalk.
The pedestrian environment can
also be uncomfortable at times
due to narrow or incomplete
sidewalks that lack street furnishings
such as benches or shade trees.
Improvements such as those
completed at the intersection of
Grand Avenue and Diamond Bar
Boulevard, as part of the Grand
Avenue Beautification Project,
serve as an excellent example of
how to make our public rights-
of-way more walkable: features,
including signature street trees with
ornamental tree grates, shrub and
ground cover plantings, enhanced
paving and pedestrian facilities,
and upgraded street furniture and
lighting, are providing a higher
standard for inviting, attractive
streetscapes.
Looking forward, streetscape
improvements that seek to create
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COMMUNITY CHARACTER & PLACEMAKING
Various combinations of streetscape
improvements are possible,
depending on a given street’s
typology and the balance of goals
related to comfort, safety, visibility,
cost, convenience, and environmental
impact. The following are common
streetscape improvements to
enhancethe public realm.
• Widening sidewalks;
• Improving the building to street
relationship at key commercial and
mixed-use areas;
• Introducing public art, gateway, and
wayfinding elements;
• Using a consistent species of trees
and planting to define corridors;
• Managing stormwater through the
use of bioswales and other ecology-
conscious features;
• Efficient materials and lighting;
• Buffering pedestrians from traffic
with landscaping;
• Adding seating and other
pedestrian-oriented furnishings;
• Improving intersections with corner
bulb-outs;
• Establishing a consistent street
signage or public signage aesthetic;
and
• Providing shaded rest areas.
STREETSCAPE
IMPROVEMENT EXAMPLES
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-10
a more active, enjoyable public
realm will be particularly influential
at existing commercial nodes
and in the mixed-use focus areas.
As streetscape improvements
are implemented, both citywide
and in the focus areas, Diamond
Bar’s street network will support
increased public activity and
pedestrian movement with
amenities such as improved
sidewalk treatments, seating,
distinctive lighting, and public
art, as well as bicycle facilities in
appropriate locations.
To this end, a new Boulevard
street typology is proposed that
emphasizes traveler experience
and sense of place on streets that
connect to major destinations
throughout the city (See Chapter 4,
Circulation). Proposed Boulevards
include Diamond Bar Boulevard
from Brea Canyon Cutoff Road to
the northern city limits; Golden
Springs Drive from SR-57 to the
northern city limits; and Grand
Avenue at the intersection of
Diamond Bar Boulevard. Boulevards
are a type of arterial that are
designed to be highly visible
and aesthetically landscaped,
incorporating wide sidewalks
adjacent to mixed-use areas
and commercial nodes where
pedestrian activity is anticipated to
be highest.
In addition to the Boulevard
typology, the General Plan outlines
an overall vision for Diamond Bar’s
streetscape design (see Chapter 4,
Circulation).
Parks and Public Open Spaces
Parks and public open spaces
are also key components of the
public realm, offering locations for
people to congregate and enjoy
leisure time among other members
of the community. As discussed
in Chapter 6, Public Facilities and
Services, Diamond Bar offers a
number of well-loved parks and
publicly accessible open spaces.
Incorporating new parks and public
spaces into new development in a
manner that encourages regular
use will contribute to livability
on the neighborhood scale by
ensuring community recreation
and gathering spaces close to
new homes, while also helping to
maintain the citywide parkland
standards. This chapter provides a
framework for designing new parks
and public open spaces that are
accessible and well-integrated
into surrounding development.
Further discussion regarding parks
and open space is provided in
Chapter 5, Resource Conservation
and Chapter 6, Public Facilities and
Services.
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COMMUNITY CHARACTER & PLACEMAKING
BUILDING AND SITE DESIGN
Building and site design within new
development play a significant
role in neighborhood and city
identity. These design elements
influence experiences of places
and establish a relationship with
existing surrounding uses. Building
design and site planning occurs
through implementation documents
such as Citywide Design Guidelines
and the Zoning Ordinance. The
Policies below are intended to
complement existing regulations,
and design guidance will be
reflected as needed in an update
of the Citywide Design Guidelines
to embody the urban design
objectives set forth in this chapter.
Site Planning and Parking
Appropriate site planning and
parking requirements are important
elements of well-designed new
development. Site planning
that encourages fine-grained
development (i.e., small blocks
and building footprints) helps
to achieve a more pedestria
friendly environment and provides
opportunities for access and
connectivity to surrounding streets
and neighborhoods. Orienting
buildings and active uses to
public spaces and public streets
further contributes to pedestrian-
friendliness by providing visual
interest for those on foot. This
fine-grained, pedestrian-friendly
development is what is envisioned
to occur in the new mixed-use focus
areas. In addition, site-planning
approaches such as right-sized
parking requirements and parking
design strategies, including locating
parking to the rear or side of
parcels, can help to create more
walkable, memorable places.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-12
Building Massing and Design
Building massing refers to the visual dominance
of buildings, while building design refers to a
building’s architectural features. Building massing
and design controls are crucial for ensuring
appropriate, sensitive development, particularly
when it is adjacent to existing residential
neighborhoods. Building massing and design
measures to be considered include providing for
sensitive transitions between new and existing
development so as to reduce impacts to existing
neighborhoods, incorporating human and
pedestrian-scaled design for new commercial
and mixed-use development, and building design
that incorporates visual quality and interest to
contribute to placemaking.
Hillside Development
Hillsides form a key part of Diamond Bar’s
identity, and the community has expressed
a desire to preserve public vistas of hillside
features. Preserving hillside views could occur
through zoning and development controls that
reduce the visual impact on hillsides by way of
alternative lot layouts, and by taking advantage
of existing site features for screening, where
development is allowed. In many cases, the City’s
Hillside Management regulations may restrict
development on hillsides. Additional direction
regarding the intensity of hillside development is
provided in Chapter 2, Land Use and Economic
Development.
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
OVERALL CHARACTER AND DESIGN
See Chapter 2: Land Use and Economic Development
for additional policies regarding land use designations.
GOALS
CC-G-1 Foster and maintain a distinctive city
identity that values the community’s
“country living” character by preserving
the city’s open spaces, physical
features, and environmental resources,
and focusing new development into
accessible, pedestrian-oriented areas
integrated with existing neighborhoods,
augmented with parks, and connected
by an attractive and safe street network.
CC-G-2 Encourage development within mixed-use
areas that is inviting to pedestrians,
promotes community interaction
and activity, and contributes to an
engaging street environment.
CC-G-3 Encourage rehabilitation and façade
improvements of existing commercial
centers to ensure commercial vitality
and pedestrian-oriented design.
CC-G-4 Preserve the scale and character of existing
residential neighborhoods
and ensure sensitive transitions
between densities and uses.
CC-G-5 Provide an expanded pedestrian and
bicycle infrastructure network to improve
connectivity throughout the city where
topography and technology permit.
CC-G-6 Encourage high-quality, human-scaled
design and development that respects
the surrounding built environment while
offering a diversity of building types.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040GUIDING POLICIES | 2020-2040 Diamond Bar General Plan Update3-14
MIXED-USE FOCUS AREAS
The focus areas build on the basic components of Diamond Bar’s existing
structure—its residential neighborhoods and commercial centers—to
establish new mixed-use areas that accommodate housing, retail, and
entertainment uses as well as community gathering places. The location
of these mixed-use focus areas within the overall city structure is shown in
Figure 3-1, Urban Design Framework. Key design features within the Urban
Design Framework include:
• An attractive Town Center at
the intersection of Diamond Bar
Boulevard and Golden Springs
Drive with active street frontages
and a pedestrian-oriented design.
• A Neighborhood Mixed-Use Area
with places to live, play and
gather, as well as connections to
surrounding neighborhoods.
• A Transit-oriented development
around the City of Industry’s major
regional transit hub: the Metrolink
station.
• Gateways at the main entrances
to the city and to the new mixed-
use areas to celebrate the unique
identity of Diamond Bar.
• New placemaking elements to be
incorporated throughout the city
such public art and as a to the
identity of Diamond Bar.
• Appropriate transitions that
emphasize building design and
articulation that is sensitive to
existing surrounding development
intensities.
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
POLICIES
City Identity
CC-P-1 Develop visual gateways at entry points to the
city and at the entrances to the
Neighborhood Mixed Use, Town Center,
Transit-Oriented Mixed Use, and Community
Core areas. Establish a gateway design
palette and guidelines consistent with
the existing gateway at Grand Avenue
and Longview Drive, employing the
same or a similar elements of streetscape
design, monument signage, lighting,
and building massing and setback.
CC-P-2 Incorporate prominent corner architectural
features, such as prominent entries or
corner towers, on new development
at key intersections or gateways.
CC-P-3 Encourage new mixed-use development to
incorporate public art that celebrates
the history and character of Diamond Bar
to reinforce community identity, create
unique places, and provide a basis for
community pride and ownership. Encourage
diversity in content, media, and siting to
reflect an array of cultural influences.
CC-P-4 Continue to support community identity with
streetscape improvement and beautification
projects in both existing residential areas
and commercial centers, as well as new
mixed-use areas that incorporate unified
landscaping and pedestrian amenities.
Amenities should include seating, bus
shelters, pedestrian safety treatments such
as sidewalk bulb-outs and widening and
improved crosswalks, and city-branded
decorative elements such as street lighting,
concrete pavers, tree grates, and theme rails.
3-16 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
CC-P-5 Establish a landscaping palette made up of
native, drought-tolerant plants and
stormwater management systems with
a view to enhancing beautification and
sustainable landscaping practices.
CC-P-6 Prioritize sustainability in site design. When
incorporating on-site stormwater management
through the use of bioswales, rain gardens,
permeable pavement, and/or other
available low-impact development
technologies, require such features to be
aesthetically integrated into the site design.
Streetscapes and Building to Street Interface
CC-P-7 Ensure that new development provides an
integrated pattern of roadways, bicycle
routes and paths, and pedestrian connections
within and between neighborhoods that
are safe, comfortable, and accessible
sidewalks for people of all ages and abilities.
CC-P-8 Where sound walls or perimeter walls or
fences are permitted, they should be
stylistically integrated with adjacent structures
and terrain, and to use landscaping and
vegetation to soften their appearance.
CC-P-9 Encourage pedestrian orientation in mixed-
use development using a variety of site
planning and architectural strategies,
such as locating and orienting buildings
to street frontages, plazas, or pedestrian
paseos; providing visual transparency
through fenestration; entries and arcades
close to the street edge and sidewalk;
and/or incorporating porches, patios,
or outdoor spaces that overlook or
interact with front yards or sidewalks.
CC-P-10 Maintain an open relationship between
buildings and the street edge, avoiding
fencing and significant landscape
barriers but incorporating street trees
and other landscaping where possible.
3.0
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
CC-P-11 In residential and mixed-use areas, use
traffic calming measures such as pavers,
bollards, sidewalk bulb-outs, and
speed humps to slow travel speeds.
CC-P-12 Develop and enforce private slope
maintenance standards for properties
with rear descending slopes that face
public streets, with special emphasis on
those along Grand Avenue, Diamond
Bar Boulevard, Golden Springs Drive,
Pathfinder Road, and the freeways.
Parks and Open Spaces
CC-P-13 Encourage landscaped common public
spaces to be incorporated into
new mixed-use development.
CC-P-14 Ensure that public spaces are physically and
visually accessible from the street,
compatible with Crime Prevention
through Environmental Design (CPTED)
principles, with signage acknowledging
that the open space is for public use.
CC-P-15 Where public space fronts the sidewalk,
ensure that it is primarily open and
free of walls or other obstructions (not
including trees, lights, and steps). Use
landscaping strategically to identify
pedestrian entrances and articulate
edges for plazas and courtyards.
CC-P-16 Ensure that common spaces be integrated
elements of development, coordinating
landscaping and amenities with the
projects’ architecture and character.
3-18 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
Site Planning and Parking
CC-P-17 Encourage the aggregation of individual
small lots into larger development parcels
within mixed-use areas that will support
an appropriately-scaled, cohesive and
economically viable development.
CC-P-18 As large vacant or underutilized sites are
developed or redeveloped, maximize multi-
modal accessibility with fine-grained street
networks and walkable block sizes. Generally
limit new block sizes to a maximum of
about 400 feet in length. Mid-block plazas
or alleys may be considered if the intent
is to ensure fine-grained patterns where
pedestrian access can be accommodated
in intervals no more than 400 feet apart.
CC-P-19 Through development review, ensure that
new development provides an
integrated pattern of streets and
pedestrian paths with connections
within and between neighborhoods.
CC-P-20 Create pedestrian-and bicycle-only
pathways to enhance neighborhood
interconnectivity where street
connections are limited due to existing
cul-de-sac or dead-end conditions,
grade separation, property ownership,
or topographical challenges.
CC-P-21 Site plans should be designed to create
pedestrian-oriented neighborhoods
that follow these guidelines:
a. Buildings should be oriented
to the street;
b. Garages and parking areas should be
screened and/or located at the side or
rear of properties wherever possible; and
c. Landscaping, sidewalk conditions, and
other streetscape elements should
be improved during rehabilitation
and new construction.
3.0
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
CC-P-22 Orient buildings adjacent to public spaces
such that entries, windows, and seating
areas face the public space.
CC-P-23 Where appropriate and feasible, locate and
orient active uses (such as commercial
uses and parks) along the street edges
of new mixed-use development, at
street corners, or along main roadways
internal to larger developments.
CC-P-24 Locate parking areas to the rear of lots while
ensuring they are accessible
from minor roadways.
CC-P-25 Encourage the design of shared parking for
commercial and office uses where possible.
CC-P-26 Establish reduced minimum commercial
parking requirements for all development
within new mixed-use land use designations.
Reduced parking requirements should
be supported by proximity to transit,
shared parking, and technologies that,
once mainstreamed, would reduce the
need for conventional parking layouts.
CC-P-27 Establish standards to ensure that garages
do not dominate streetscapes in
residential areas. Encourage the design
of recessed or side-loaded garages.
Building Massing and Design
CC-P-28 Ensure that new development does not cast
significant shadows over existing
development. Require detailed
shadow studies as part of development
review where appropriate.
CC-P-29 Promote the revitalization of existing
commercial centers by encouraging
property owners to maintain and improve
the appearance of individual buildings
and commercial centers through building
façade improvements, landscaping,
and pedestrian improvements.
3-20 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
CC-P-30 Ensure that infill residential development is
designed to be sensitive to the
scale, character, and identity of
adjacent existing development.
CC-P-31 Ensure that commercial uses are designed
to incorporate ground floor transparency
and pedestrian activity.
CC-P-32 Emphasize human-scaled design within
large-scale commercial and mixed-
use centers. Employ measures such
as articulated massing, awnings,
and landscape elements to break
down the scale of development.
CC-P-33 Encourage new mixed-use and commercial
development to incorporate visual
quality and interest in architectural
design on all visible sides of buildings
through the following approaches:
a. Utilizing varied massing and roof types,
floor plans, detailed planting
design, or color and materials;
b. Maintaining overall harmony while
providing smaller-scale variety; and
c. Articulating building facades with
distinctive architectural features
like awnings, windows, doors,
and other such elements.
CC-P-34 Update the City of Diamond Bar Citywide
Design Guidelines as needed
to reflect the design guidance
articulated in the General Plan.
CC-P-35 Ensure the protection of views of hillsides
and ridges from public streets, parks, trails,
and community facilities by requiring a
visual impact analysis for new development
that identifies potential impacts to visual
resources as well as feasible measures
to mitigate any potential impacts.
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
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COMMUNITY CHARACTER & PLACEMAKING
3.3 FOCUS AREAS
As is discussed in Chapter 2, Land
Use and Economic Development,
focus areas are proposed where
new mixed-use development is to
be concentrated to accommodate
housing, retail, and entertainment
uses, as well as community
gathering places. To successfully
integrate into the community,
the focus areas will need to be
designed to respect existing
surrounding development while
establishing their own unique
identities and encouraging
pedestrian comfort and
connectivity through active street
frontages and site design that favors
a more pedestrian-friendly building
to street relationship. Four focus
areas within the city are shown in
Figure 3-1: Neighborhood Mixed-
Use; Town Center, Transit-Oriented
Mixed-Use, and Community Core.
See Chapter 2, for descriptions of
each focus area as well as their
associated land use classifications.
Figures of each focus area are
intended only to illustrate possible
land use and urban design
frameworks that implement the
corresponding policies for those
focus areas.
NEIGHBORHOOD MIXED USE FOCUS AREA
The North Diamond Bar Boulevard
corridor is dominated by aging
commercial centers. The General
Plan envisions the corridor as
redeveloping with a vibrant mix of
uses, including residential with a
range of housing types including
parks and gathering places,
together with neighborhood-serving
commercial uses clustered at key
nodes. Given its proximity to existing
residential neighborhoods, it will be
important to design development
in this focus area to respect the
character of surrounding residential
neighborhoods. Site plans that
encourage walkable and bikeable
neighborhood design through
pedestrian pathways, streetscape
improvements and traffic-calming
measures would also contribute
to the connectivity of the focus
area to adjacent neighborhoods,
including the Town Center. Figure
3-2 is intended only to illustrate
possible land use and urban design
frameworks that implement the
corresponding policies for the
Neighborhood Mixed Use focus
area.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-22
Figure 3-2: Neighborhood Mixed-Use Focus Area Concept Illustration
Armstrong
E.S.
Diamond
Point
E.S.
Golden
Springs
E.S.
57
Union PRailroadSouthern Pacic RailroadW
T
EM
P
L
E
A
V
E
DIAMON D B A R B L V D
SUNSET CROSSING RD
B
A
LLENA DR
PALOMI
N
O
D
R
D E C O R A H R D DEL SOL LNHIGHLAN D VA L L E Y R D
EL ENCINO DRROCK RIVER DRHA
P
P
Y
H
O
L
L
O
W
R
D
W IL L O W CREEK0 1/21/4
MILES
P
N-MU area
Majority commercial frontage
Public parkland
Building orientation
Parking area
Landscaped path/walkway
Figure 3-2: Neighborhood Mixed-Use (N-MU) Conceptual Illustration
P
P
P 1,000 feetCommercial development required
along a majority of the corridor
frontage 1,000 feet south of
Highland Valley Rd.
On-site public parkland required
on all sites over 4 acres
Buildings along the corridor
oriented to face the street
Landscaped walkways that connect
the area and promote neighbor-
hood integration and walkability
Parking consolidated and located
to the side or rear of buildings
Improvements to enhance
pedestrian comfort along the
Diamond Bar Blvd corridor,
including shade trees and pedes-
trian furniture
Buildings along the corridor
oriented to face the street
mented along Diamond Bar Blvd
between Temple and Sunset
Crossing to improve pedestrian
comfort and safety
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
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3-23
COMMUNITY CHARACTER & PLACEMAKING
TOWN CENTER MIXED USE FOCUS AREA
While the Town Center area
is currently functioning as a
commercial center and has
undergone recent redevelopment,
it is envisioned that the Town
Center area will undergo further
new and infill development and
improvements that would allow
it to evolve into an attractive,
walkable destination, with a greater
concentration of retail and dining
establishments and public open
spaces such as patios and plazas.
Residential uses are also supported
as secondary to commercial
uses. Given the proposed role of
the Town Center as a community
destination and gathering place,
it will be essential to strengthen
multi-modal connections and
enhance safety of pedestrian
crossings so as to connect uses
across Diamond Bar Boulevard and
improve access to the Town Center
for community members of all ages
and abilities. Figure 3-3 is intended
only to illustrate possible land use
and urban design frameworks
that implement the corresponding
policies for the Town Center Mixed
Use focus area.
TRANSIT-ORIENTED MIXED USE FOCUS AREA
Development opportunities
within the Transit-Oriented Mixed
Use focus area are located
principally within the cluster of
parcels currently occupied by light
industrial uses directly adjacent
to the Metrolink station. High
density housing, including live/
work units, that leverages access
to the neighboring transit facilities
(Metrolink Industry Station and
Foothill Transit City of Industry Park
& Ride) and supporting commercial
uses is envisioned for this area. Site
design that promotes multi-modal
access within neighborhoods
and to the station will be an
important consideration to facilitate
access and connectivity. New
development should also be
compatible with potential noise and
air pollution sources such as SR-60
and Union Pacific Railroad right-of-
way, while respecting surrounding
residential neighborhoods. Figure
3-4 is intended only to illustrate
possible land use and urban design
frameworks that implement the
corresponding policies for the
Transit-Oriented Mixed Use focus
area.
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-24
Figure 3-3: Town Center Mixed-Use Focus Area Concept Illustration
DI
AMOND BAR BLVDPROSPECTORS RDGOLD RUSH DR
PALOMI
N
O
D
R
D E C O R A H R D
S. RANC
H
E
R
I
A
R
D
B E AVERHEAD D R
6057
GOLD E N S P R IN G S D RArmstrong
E.S.
Lorbeer
Junior H.S.
P
N-MU area
Public park or plaza
Building orientation
Parking area
Landscaped path/walkway
0 1/21/4
MILES
Improved Pedestrian Crossing
P
Figure 3-3: Town Center Mixed Use (TC-MU) Conceptual Illustration
Potential for new main street or
landscaped pedestrian network,
providing for smaller-scale retail,
and enhancing Town Center
character
Enhanced pedestrian comfort at
intersections and along Diamond
Bar Blvd and Golden Springs Dr
the public realm
Parking consolidated and located
to the side or rear of buildings
Discourage new drive-through
uses
Surface parking repurposed to
create central gathering places
such as parklets or plazas
Buildings and streetscapes dene
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING 3-25
Figure 3-4: Transit-Oriented Mixed Use Focus Area Concept Illustration
Walnut
E.S.Riverside Metrolink Line
60Southern Pacic Railroad57
G O LD E N S P R I N G S D R
BREA CANYON RDLEMON A VELYCOMING ST
BRIDGEGATE DRMetrolink
Station
AERBCANYON
RDVALLEY VISTA DRWASHINGTON AVE
0 1/21/4
MILES
PTOD-MU area
Public parkland
Parking area
Pedestrian connection
Figure 3-4: Transit-Oriented Mixed-Use (TOD-MU) Conceptual Illustration
1/4-mile r
a
di
u
s
On-site public parkland required
on all sites over 4 acres
Consolidation of small
parking lots and district-wide
parking management
1/4-mile radius of the Metrolink
Station and surrounding high-density
uses promotes connectivity
High-density housing clustered
west of Lemon Ave and adjacent
to the Metrolink Station
Building frontages and streetscape
realm and encourage pedestrian
activity and comfort
Safe, convenient and comfortable connec-
tions between the TOD-MU focus area and
surrounding neighborhoods
Connect roadways
where possible
Retail clustered at a commercial
node along Brea Canyon Rd
P
P
A ne-grained block pattern within a
designed to dene the public
COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 20403-26
COMMUNITY CORE FOCUS AREA
The Community Core Overlay
encompasses the Diamond Bar
Golf Course, and would apply
should the golf course close or
cease operations. The golf course,
which is owned and operated by
Los Angeles County, features rolling
terrain and benefits from great
regional access. The Community
Core Overlay would allow for
development in the portion of the
Golf Course south of Grand Avenue
and at the northeasterly corner of
Grand and Golden Springs—in the
general location of the clubhouse
and parking facilities—while
envisioning approximately 100
contiguous acres to be open park
and civic uses.
Development within the Community
Core would be master-planned
and envisioned to create a
vibrant, mixed-use, pedestrian-
oriented community and regional
destination, with commercial uses,
dining, and entertainment uses;
residential uses; and supporting
offices and hotels. While the range
of uses would be similar to the
Town Center, the area would be
developed from the ground up to
function as a walkable destination,
featuring close integration of a
variety of uses and public gathering
spaces.
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
NEIGHBORHOOD MIXED USE FOCUS AREA
See Chapter 2: Land Use and Economic Development for
additional policies regarding allowable uses, densities,
and intensities in the focus areas.
GOALS
CC-G-7 Create a well-designed, walkable, mixed-
use neighborhood that encourages
community interaction, showcases
the city’s identity, and is integrated
with residential uses to the east.
CC-G-8 Promote vertical and horizontal mixed-use
development along Diamond Bar Boulevard.
CC-G-9 Encourage development that takes
advantage of the focus area’s dramatic
topography by establishing unique open
spaces and open space connections.
CC-G-10 Establish a visual gateway into the city at the
north end of the focus area.
POLICIES
CC-P-36 Develop specific building height and other
development standards through
implementation mechanisms such
as the City’s Development Code
and master or specific plans.
CC-P-37 Where possible, require that adjacent
commercial uses share driveways in
order to limit the number of curb cuts
along North Diamond Bar Boulevard.
CC-P-38 Enhance the pedestrian experience along
the east side of Diamond Bar Boulevard
within the Neighborhood Mixed Use area
with widened sidewalks, shade trees,
and pedestrian amenities such as street
furniture, attractive paving, pedestrian-
scaled lighting, and landscape buffers.
Front setbacks should function as an
extension of the sidewalk, with publicly-
accessible and usable open space.
3-28 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
CC-P-39 Enhance pedestrian comfort on the west
side of North Diamond Bar Boulevard
through enhanced landscaping
and improved fencing.
CC-P-40 To the extent possible, locate parking such
that is it concealed from view from
North Diamond Bar Boulevard and
connected via landscaped walkways.
TOWN CENTER MIXED USE FOCUS AREA
GOALS
CC-G-11 Support an intense mix of active uses on
both sides of Diamond Bar Boulevard
within the Town Center focus area.
CC-G-12 Establish an inviting and comfortable public
realm that encourages pedestrian
activity in the Town Center focus area.
CC-G-13 Establish a new pedestrian-oriented “Main
Street” within the Town Center focus
area lined with retail uses.
POLICIES
CC-P-41 Through development review, ensure that
the Town Center remains predominantly
a community shopping, dining, and
entertainment destination, and that
residential uses and offices are located
so as not to detract from this image.
CC-P-42 Prioritize retail and other uses that promote
pedestrian activity on the ground floor of
buildings.
CC-P-43 Establish gateways to the Town Center area
at the intersections of Diamond Bar
Boulevard and Golden Springs Drive and
at Diamond Bar Boulevard and Palomino
Drive. Gateway elements should be
consistent with the gateway design palette.
3.0
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
CC-P-44 As the Town Center redevelops, enhance
pedestrian connectivity throughout the
district through the incorporation of a
new “Main Street” within the western
portion of the focus area that is off of or
set back from Diamond Bar Boulevard.
CC-P-45 The design of new development should be
pedestrian-oriented, with the majority
of building frontages located at the
new street edge and with entrances
located along the roadway or along
pedestrian pathways or public spaces.
CC-P-46 Ensure that new buildings employ horizontal
and vertical building articulation and
diversity in color, materials, scale,
texture, and building volumes.
CC-P-47 Develop specific building height and other
development standards through
implementation mechanisms such
as the City’s Zoning Ordinance or a
master or specific planning process.
CC-P-48 Encourage dining establishments to
incorporate outdoor dining
or sidewalk cafés.
CC-P-49 Encourage reductions in surface parking
and allow for the development of
consolidated parking structures,
provided that they are screened from
view from Diamond Bar Boulevard
and Golden Springs Drive.
CC-P-50 Where possible, above-grade parking
structures should be wrapped with
pedestrian uses where they front onto
active streets. If active uses are not
feasible, frontages should be architecturally
attractive. This may include unique designs
and materials such as glass, articulated
masonry, murals, or landscaping setbacks.
3-30 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
CC-P-51 Enhance the pedestrian experience along
Diamond Bar Boulevard within the
Town Center area with widened
sidewalks, shade trees, and pedestrian
amenities such as street furniture,
attractive paving, pedestrian-scaled
lighting, and landscape buffers.
Transit-Oritented Mixed-Use Focus Area
GOALS
CC-G-14 Create an engaging, compact, mixed-use
neighborhood that encourages multi-
modal transportation and responds
to a diversity of housing needs.
CC-G-15 Incorporate into site design spaces for
recreation, community gathering,
amenities, and services to fulfill the needs
of nearby current and future residents.
CC-G-16 Ensure that new development is sensitive to
the scale of adjacent residential uses and
potential sources of noise and air pollution.
POLICIES
CC-P-52 Highlight gateways and access to the transit
facilities through landscape and
signage improvements.
CC-P-53 Create a node of commercial activity at the
northwest corner of Brea Canyon
Road and Washington Street, with
development oriented to the street.
CC-P-54 Encourage all new development within a
quarter-mile radius of the transit
facilities to focus building design,
massing, and landscaping toward the
pedestrian experience through:
a. Limiting block lengths between streets
generally to a maximum of 400 feet,
and encouraging four-way intersections;
3.0
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GOALS & POLICIES
Diamond Bar General Plan 2040 | COMMUNITY CHARACTER & PLACEMAKING
b. Providing space for enhanced
pedestrian connections such as
internal semi-public pathways;
c. Building design that focuses
on street orientation;
d. Extensive landscaping and street trees;
e. Pedestrian furniture and site elements
(for example, benches and
trash receptacles);
f. Street lighting; and
g. Wayfinding signage.
CC-P-55 Promote internal connectivity where street
connections are limited by incorporating
multi-use pathways internal to new
development and connecting to existing
development. Ensure that pathways are
continuous, bikeable, and visible from
the roadway and transit facilities.
CC-P-56 Promote pedestrian and bicycle
connections to the Metrolink station, making
use of existing infrastructure that connects
South Brea Canyon Road to the station.
CC-P-57 Improve the pedestrian comfort and safety
of crosswalks along South Brea Canyon
Road and South Lemon Avenue.
CC-P-58 Enhance the pedestrian experience along
South Brea Canyon Road within the
Transit-Oriented Mixed Use area with
widened sidewalks, shade trees, and
pedestrian amenities such as street
furniture, attractive paving, and pedestrian
scaled lighting, where feasible.
CC-P-59 Consolidate parking underground or in
shared structures away from the street
edge where possible. Above-grade
parking structures should be wrapped
with residential uses where they front
onto active streets. If active uses are not
3-32 COMMUNITY CHARACTER & PLACEMAKING | Diamond Bar General Plan 2040
feasible, frontages should be architecturally
attractive. This may include unique designs
and materials such as glass, articulated
masonry, murals, or landscaping setbacks.
Community Core Focus Area
GOALS
CC-G-17 Create a new master-planned destination
with vibrant, mixed-use, pedestrian oriented
uses for the community and region.
POLICIES
CC-P-60 Buildings should be designed to define the
public realm and promote sidewalk
activity and public spaces for
neighborhood interaction.
CC-P-61 Develop specific building height and other
development standards through
implementation mechanisms such
as the City’s Zoning Ordinance or a
master or specific planning process.
CC-P-62 Create a fine-grained pedestrian-scaled
street network and ensure that
buildings and streetscapes encourage
pedestrian activity and comfort.
CC-P-63 Parking should be consolidated and
located in a manner that encourages
pedestrian activity. Avoid
expanses of surface parking.
CC-P-64 Provide streetscape and intersection
improvements along Golden Springs Drive
to enhance comfort and safety for all
modes of travel and increase accessibility
to and from surrounding areas.
The Circulation Chapter
provides goals and policies
aimed at improving the
transportation network
within the City, balancing
the vehicular circulation
needs with safety and access
across a variety of modes
of transportation through a
Complete Streets approach.
CIRCULATION 4.0
CIRCULATION | Diamond Bar General Plan 20404-2
4.1 INTRODUCTION
This chapter identifies various
transportation systems in the
City to create a complete
transportation network, including
automobile travel, transit, non-
motorized transportation, and
goods movement. Other aspects
of circulation such as parking
and emergency access are
also addressed in this chapter.
The policy direction established
in this chapter supports other
chapters of the General Plan by
providing and enhancing multi-
modal transportation options and
supporting adjacent land uses.
RELATIONSHIP TO STATE LAW
State law (Government Code
Section 65302(b)(1)) requires general
plans to include a circulation
element consisting of the general
location and extent of existing and
proposed major thorough- fares,
transportation routes, terminals,
any military airports and ports,
and other local public utilities
and facilities, all correlated
with the land use element of
the plan. This chapter is closely
tied to Chapter 2: Land Use and
Economic Development as it seeks
to provide sufficient transportation
capacity for all travel modes
to accommodate the mobility
needs of existing and planned
development.
This chapter reflects important
policy changes across California
including the California Complete
Streets Act (Assembly Bill [AB]
1358), which requires general
plans updated after January 30,
2011 to incorporate Complete
Street policies and frameworks.
Complete Streets policies aim to
provide a balanced, multi-modal
transportation network that meets
the needs of all users of streets,
roads, and highways for safe and
convenient travel in a manner that
is suitable to the rural, suburban, or
urban context of the general plan.
Other considerations of this plan
include Senate Bill (SB) 32, which
Diamond Bar General Plan 2040 | CIRCULATION
4.0
4-3
CIRCULATION
requires California to reduce
greenhouse gas (GHG) emissions
to 40 percent below 1990 levels
by 2030, and Executive Order
B-16-12, which provides a target of
80 percent below 1990 emissions
levels for the transportation sector
by 2050. Executive Order B-55-18
directs the State to be carbon
neutral by 2045. The California
Air Resources Board (CARB) has
determined that it will not be
possible to achieve the State’s
long-term climate goals without
reducing per capita vehicle miles
traveled (VMT) growth, given that
the transportation sector is the
State’s largest source of air pollution
and GHG emissions. To this end, SB
743 has amended the California
Environmental Quality Act (CEQA)
guidelines related to the analysis of
transportation impacts. Specifically,
the guidelines shift from the
traditional vehicle-based level of
service (LOS) analysis to VMT, which
better evaluates goals related to
sustainability, accessibility and
multi-modal transportation options.
Nevertheless, the City recognizes
the continued importance of
LOS to ensure efficient vehicular
movement and prevent congestion
and traffic delays. LOS standards
are thus established in the
Circulation Chapter to help
decision-makers understand traffic
conditions and guide strategic
improvements to the roadway
network.
RELATIONSHIP TO OTHER ELEMENTS
This chapter relates to Chapter
2, Land Use and Economic
Development, Chapter 5,
Resource Conservation, and
Chapter 8, Community Health
and Sustainability. As referenced
above, this chapter is closely tied
to the Land Use and Economic
Development in that it seeks to
lay out a transportation network
and transportation capacity for
all travel modes to accommodate
the mobility needs of existing
and planned land uses and
development. The transportation
system supports other chapters of
the overall General Plan including
Resource Conservation (Chapter
5) and Community Health and
Sustainability (Chapter 8) by
providing and enhancing safe
multi-modal transportation options
that link parks, open spaces, and
regional hiking trails; integrating
opportunities for physical activity
into daily life; and providing
approaches to reduce vehicle
emissions to improve air quality and
reach State GHG targets.
CIRCULATION | Diamond Bar General Plan 20404-4
4.2 TRANSPORTATION NETWORK
According to the U.S. Census, as of
2019 the vast majority of commuters
in Diamond Bar drive to work,
most often using single-occupant
vehicles.1 The single-occupant
vehicle mode share for Diamond
Bar is higher than the average
for Los Angeles County and the
state. Chief among the reasons
for this high level of vehicular
travel is the City’s existing land use
pattern, which is primarily suburban
residential which requires residents
to travel longer distances for work
and to serve daily needs. While it
is anticipated that vehicular travel
will remain Diamond Bar’s dominant
mode share during the horizon
of this General Plan, the Plan
seeks to reduce single-occupant
vehicle mode share and VMT in line
with State goals and regulations
by introducing new mixed-use
development and facilities for
alternative modes of transportation
such as bicycles and pedestrians.
COMPLETE STREETS
As mentioned above, California
passed the California Complete
Streets Act in 2008, requiring
circulation elements to include a
complete streets approach that
balances the needs of all users of
the street. Complete Streets are
streets designed and operated to
enable safe access for all users,
including pedestrians, bicyclists,
motorists, and transit riders of all
ages and abilities.
The precise definition of a Complete
Street can vary depending on
the context and primary roadway
users, but there are some common
elements found in successful
Complete Streets policies. These
policies consider the needs of all
users of the street in the planning,
design, construction, operation,
and maintenance of transportation
networks (National Complete
Streets Coalition, 2017). This
framework allows policymakers to
shift the goals, priorities, and vision
of local transportation planning
efforts by emphasizing a diversity
of modes and users. While the City
of Diamond Bar has previously
maintained goals and policies to
promote a multi-modal network, this
chapter reinforces the importance
of accommodating a variety
of travel modes to balance the
transportation needs of Diamond
Bar residents through additional
Complete Streets policies.
CIRCULATION DIAGRAM
Circulation Diagram (Figure 4-1)
depicts the proposed circulation
system to support development
under the Land Use Diagram. The
system is represented by a set
of roadway classifications that
1 Note that data from the U.S. census presents limitations in that it doesn’t allow individuals to select more than one mode
of travel, should they split their commute between modes, and it doesn’t account for non-work trips such as errands, trips
related to recreation, or school drop-offs and pick-ups, which represent an important proportion of trips in any given
place. It is thus possible that the single-occupant vehicle mode share of non-commute trips is lower.
Diamond Bar General Plan 2040 | CIRCULATION 4-5
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Figure 4-1: Circulation Diagram City of Diamond Bar
GENERAL PLAN UPDATE
Source: Fehr & Peers, 2019;
City o f Diamond Bar, 2019; Dyett & Bhatia, 2019
Figure 4-1 Circulation Diagram
CIRCULATION | Diamond Bar General Plan 20404-6
have been developed to guide
long range transportation planning
in Diamond Bar to balance access
and capacity. The classification
system consists of freeways,
arterials, boulevards, collectors,
and local roadways. Functional
classification refers to how a road
accommodates two characteristics:
first, the extent to which the roadway
prioritizes the through movement
of vehicular traffic; and second,
the level of access provided to
adjacent properties. Based on these
generalized characteristics, roadways
often vary in terms of right-of-way,
roadway width, number of lanes,
intersection and traffic signal spacing,
speed, and other factors. In addition,
they may contain elements such as
pedestrian or bicycle infrastructure
to comply with a Complete Streets-
based approach to mobility.
ROADWAY CLASSIFICATIONS
Diamond Bar’s proposed roadway
classifications described below.
Table 4-1 summarizes the roadway
classifications and provides high-level
design characteristics. Additional
roadway design details are provided
within the Standard Drawings used by
the City of Diamond Bar Public Works
Department.
Freeways
Freeways generally provide high
speed, high capacity inter-regional
access. Their primary function is to
move vehicles through or around
the city; thus, there is no access to
adjacent land, and limited access
to arterial streets. Freeways contain
anywhere from 4 to 12 lanes with
recommended design volumes from
80,000 to 210,000 vehicles per day.
Arterials
Arterial streets carry the majority
of traffic traveling through the City.
They serve two primary functions:
to move vehicles into and through
the city, and to serve adjacent
commercial land uses. They provide
access to freeways as well as major
activity centers and residential areas.
Driveways and other curb cuts along
arterials are generally designed to
minimize disruption to traffic flow.
Sidewalks are typically included
along arterials, and protected Class I
or IV bike lanes are permitted.
The desired maximum roadway
capacity on arterials averages from
30,000 to 45,000 vehicles per day
depending on number of lanes, type
and width of directional separation,
presence of on-street parking or
bicycle facilities, configuration and
frequency of access to adjacent land
uses, and intersection configurations.
(Bike route classifications are defined
in Section 4.4—Pedestrian and Bicycle
Circulation.)
Boulevards
Boulevards are a type of arterial
designed to connect major
destinations within the City, and
are highly visible and aesthetically
landscaped with shade trees and
wide sidewalks. Boulevards provide
consolidated access to adjacent
commercial and residential uses while
balancing the needs of motorists,
bicyclists, and pedestrians with
sidewalks and protected bicycle
facilities.
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CIRCULATION
Description Local Collector Boulevard Arterial Freeway
Vehicular
Travel Lanes
2 2-4 2-4 4+4+
Speed Limit 25 mph 25-35 mph 25-55 mph 25-55 mph 65 mph
Level of
Service
Standard
D D D D D
Average Daily
Trips
Up to 2,500 Up to 20,000 30,000 - 45,000 30,000 - 45,000 80,000 -
210,000
Access Individual
parcel
access.
Some individual
parcel access,
with connection
to schools, parks,
shopping centers,
secondary
collectors and
arterials
Emphasis on
limiting individual
lot access, instead
encourage joint
driveways, back-
up lots and access-
ways to reduce
driveways.
Emphasis on
limiting individual
lot access, instead
encourage
joint driveways,
back-up lots and
access- ways to
reduce driveways.
Grade
separated
interchanges
Parking Typically
permitted
May be permitted May be permitted May be permitted Prohibited
Bicycle
Facilities
Shared
roadway
Class II or Class IV Class II or Class IV Parallel Class I or
Class IV
None
Pedestrian
Facilites
Sidewalk Sidewalk Sidewalk Sidewalk None
Note: One service level deviation may be permitted for projects that support other goals from the General Plan
including transit, active transportation and economic development consistent with goal CR-G-7 and policies CR-P12,
CR-P-14, and CR-P-16.
Table 4-1: Hierarchy of Streets and Street Standards
The desired maximum roadway
capacity on boulevards averages
from 30,000 to 45,000 vehicles
per day depending on number of
lanes, type and width of directional
separation, presence of on-street
parking and bicycle infrastructure,
configuration and frequency of access
to adjacent land uses, and intersection
configurations.
Collectors
Collectors are intended to carry traffic
between the arterial street network
and local streets or directly from the
access drives of higher intensity land
uses. Collectors serve commercial,
residential, or public uses, and are
generally two- or four-lane roadways
with sidewalks and Class II or Class IV
bicycle facilities. The desired roadway
capacity on a collector street can
average up to 20,000 vehicles per day.
Local Streets
Local streets are designed to serve
adjacent land uses only. They allow
access to residential driveways
and often provide parking for the
neighborhood. They are not intended
to serve through traffic traveling from
one street to another, but solely local
traffic. Sidewalks and shared bicycle
facilities are appropriate on local
streets. The desired roadway capacity
on a residential street should not
exceed about 2,500 vehicles per day
and 200-300 vehicles per hour during
peak periods. The maximum residential
traffic volume that is acceptable to
CIRCULATION | Diamond Bar General Plan 20404-8
Examples of curbside management best practices include:
• Collecting data to create a curb use data inventory;
• Ensuring that pick-up/drop-off areas are in safe locations;
• Configuring roadways to ensure that they do not interfere with
bike lanes;
• Accounting for
loading and parking
needs; and
• Incorporating “flex
spaces” that can
allow a curb space to
play many roles (such
as loading, parking,
or public space) over
time depending on
demand.
CURBSIDE MANAGEMENT EXAMPLES
CURBSIDE MANAGEMENT
Curbside management is a crucial
aspect of any transportation
network. The curbside is the public
space in a transportation network
“where movement meets access.”
Curb space has traditionally been
used to accommodate private
vehicle storage or on-street
parking; however, cities are
increasingly recognizing the need
to accommodate demand for
curbside use generated by transit
boarding, emergency vehicle
access, ADA access, bicycles
and bicycle infrastructure, taxis,
transportation network companies
(TNCs), and delivery vehicles. The
development of a set of curbside
management guidelines could help
Diamond Bar balance the needs of
these different curbside users.
persons living along a street may
vary from one street to another
depending on roadway width, type
of dwelling units (i.e., high density
apartments versus single-family
homes), presence of schools and
other factors. The maximum volume
of 2,500 is, therefore, to be used as
a guide only, and a neighborhood’s
sensitivity to potential impacts need
to be carefully considered.
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GOALS & POLICIES
TRANSPORTATION NETWORK AND STREET DESIGN
See Chapter 2: Land Use and Economic Development
for additional policies regarding land use designations
and street design.
GOALS
CR-G-1 Improve the operating efficiency of the
transportation system by reducing
vehicle travel demand and providing
opportunities for other modes of travel.
Before approving roadway improvements
that focus on increasing vehicle capacity,
consider alternatives that reduce vehicle
volumes and prioritize projects that
would reduce single-occupancy vehicle
use and greenhouse gas emissions.
CR-G-2 Maintain a street classification system that
considers the broad role of streets as
corridors for movement but also reflects
a Complete Streets concept that enables
safe, comfortable, and attractive access
for pedestrians, bicyclists, motorists, and
transit users of all ages and abilities,
in a form that is compatible with and
complementary to adjacent land uses,
including neighborhood schools.
CR-G-3 Strive to achieve a finer grained network of
streets and pedestrian/bicycle connections
as development occurs, especially in
focus areas such as the Transit-Oriented,
Neighborhood, Town Center, and
Community Core mixed-use areas.
CR-G-4 Design roadways serving pedestrian-
oriented mixed-use areas to
promote neighborhood interaction,
pedestrian comfort and walkability,
and commercial patronage.
CIRCULATION | Diamond Bar General Plan 20404-10
CR-G-5 Develop neighborhood streets and alleys
that encourage walking, biking, and
outdoor activity through engineering
and urban design principles that
reduce the potential for speeding
and cut-through traffic, which may
include traffic calming measures.
CR-G-6 Track the use of future transportation
options such as Transportation Network
Companies (TNCs), ride sharing, and
autonomous vehicles (AVs), and adjust City
requirements, such as roadway design or
parking standards as needed to ensure
safety and access for all users and modes.
POLICIES
CR-P-1 When redesigning streets, plan for the needs
of different modes by incorporating
elements such as shade for pedestrians,
safe pedestrian-friendly crossings/
intersections, lighting at the pedestrian
scale, bike lanes, signage visible to
relevant modes, transit amenities, etc.
CR-P-2 Promote new street designs and efforts to
retrofit existing streets in residential
neighborhoods minimize traffic
volumes and/or speed as appropriate
without compromising connectivity for
emergency vehicles, bicycles, pedestrians,
and users of mobility devices.
CR-P-3 Plan for and provide new connections within
the Transit-Oriented, Neighborhood, Town
Center, and Community Core mixed-use
areas to create finer grained, pedestrian-
scaled circulation networks that support
the development of connected and
accessible neighborhoods. Connections
should facilitate the use of alternatives to
single-occupancy vehicles, such as walking,
bicycling, and transit by improving the
safety and accessibility of those modes.
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GOALS & POLICIES
CR-P-4 Develop traffic calming strategies for
Diamond Bar Boulevard between Temple
Avenue and Golden Springs Drive in
order to provide a safe and comfortable
pedestrian-friendly environment along
and through the Neighborhood Mixed
Use and Town Center Mixed Use areas.
CR-P-5 Necessary transportation improvements
should be in place, or otherwise
guaranteed to be installed in a timely
manner, before or concurrent with new
development. In evaluating whether a
transportation improvement is necessary,
consider alternatives to the improvement
consistent with CR-G-1, and the extent
to which the improvement will offset the
traffic impacts generated by proposed
and expected development.
CR-P-6 Continue to implement congestion
mitigation measures to ensure that new
projects do not significantly increase
local City congestion based on defined
level of service (LOS) standards.
CR-P-7 Support the development of City street
design standards that:
a. Address the needs of different modes
according to roadway classification
b. Reduce the potential for conflicts and
safety risks between modes; and
c. Support and manage the use of
transportation options that will become
increasingly popular in the future, such
as TNCs, AVs, micro-transit (privately
operated transit), and other emerging
transportation technologies.
CIRCULATION | Diamond Bar General Plan 20404-12
CR-P-8 Plan for passenger pick-up/drop-off
locations within both public right-of-
way and on private properties for AVs,
TNCs, and micro-transit to limit traffic
disruptions and increase safety by
identifying and designating specific
locations for pick-ups and drop-offs.
CR-P-9 Develop a plan for managing limited curb
space throughout the City’s commercial,
mixed-use, and higher density areas to
accommodate efficient package and
food deliveries; delivery of goods to
restaurants/retail; pick-up/drop-off of
passengers by transit, taxis, and on-demand
shared ride services; and the safe
movement of pedestrians and bicyclists.
CR-P-10 Develop curbside management guidelines
that ensure curb spaces meet multi-
modal demands safely and efficiently.
CR-P-11 Implement standards for inventorying and
encoding curb use data to monitor
the effectiveness of curbside
management guidelines and provide
evidence to support or make changes
to curb space designations and/
or management strategies.
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CIRCULATION
4.3 VEHICLE CIRCULATION
As noted above, automobiles are
expected to remain the dominant
mode of transportation within the
planning horizon of the General
Plan. Diamond Bar residents
have expressed major frustration
with vehicular congestion on
the City’s roadways. For these
reasons, ensuring smooth vehicular
circulation will continue to be an
important effort for the foreseeable
future in Diamond Bar. Challenges
facing the City include regional
cut-through traffic and the tradeoffs
implied by the prioritization of other
modes of travel. Two freeways
(SR-57 and SR-60) run through the
City and along its westerly and
northerly boundaries. These heavily-
congested freeways are accessed
by several on/off-ramps throughout
Diamond Bar. Several of these
ramp intersections experience high
levels of delay during one or both
peak hour periods, and high travel
volumes along these highways can
lead to traffic cutting through the
City (on roads such as Diamond Bar
Boulevard) to avoid congestion or
transfer from one highway to the
other.
STANDARDS FOR SERVICE
Level of Service (LOS)
Given Diamond Bar’s overall
development pattern and that
Diamond Bar’s vehicular mode
share is anticipated to remain
relatively high, LOS continues to be
a useful measure of the potential
localized effects of development
and land use changes on the
transportation network and
on the efficiency of vehicular
travel. Thus, LOS continues as an
important measure of mobility in
the City even as the General Plan
seeks to balance LOS with other
considerations and measures.
LOS represents a qualitative
description of the traffic operations
experienced by the driver at an
intersection or along a roadway
CIRCULATION | Diamond Bar General Plan 20404-14
LOS Definition
Level of Service A Free-flow travel with freedom to maneuver
Level of Service B Stable operating conditions, but the presence of other
road users causes a noticeable, though slight, reduction in
convenience, and maneuvering freedom
Level of Service C Stable operating conditions, but the operation of individual
users is substantially affected by the interaction with others in
the traffic stream.
Level of Service D High-density, but stable flow. Users may experience restriction
in speed and freedom to maneuver, with poor levels of
convenience.
Level of Service E Operating conditions at or near capacity. Speeds are
reduced to a low but relatively uniform value. Freedom to
maneuver is difficult with users experiencing frustration and
poor convenience. Unstable operation is frequent, and minor
disturbances in traffic flow can cause breakdown conditions.
Level of Service F Forced or breakdown conditions. This condition exists
wherever the volume of traffic exceeds the capacity of the
roadway. Long queues can form behind these bottleneck
points with queued traffic traveling in a stop-and-go fashion
Table 4-2: Level of Service Definitions
segment. It ranges from LOS “A”,
with no congestion and little
delay, to LOS “F”, with excessive
congestion and delays. Table 4-2
provides definitions for different LOS
levels.
LOS/VMT/Community Character
Tradeoffs
With a commitment to
Complete Streets and a desire to
accommodate other users such
as pedestrians and bicyclists, it
is particularly important that LOS
thresholds, which are commonly
evaluated to determine the size and
design of the roadway system or
the feasibility of development, are
balanced with other metrics that
seek to reduce vehicle travel and
enhance community values. This
approach requires consideration of
the following tradeoffs associated
with different LOS thresholds,
which ensures that the policy will
represent clear community priorities
and provide specific exceptions
when other community values are
considered more important than
LOS:
1. Costs. Because LOS policies
influence the size and type of
transportation infrastructure
investments, maintaining a
higher LOS (e.g. LOS A, B, or C)
may be an inefficient use of
public funds when considering
the cost to build, operate, and
maintain the roadway network.
2. Safety. Higher LOS thresholds
are often associated with higher
vehicle speeds for peak and
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CIRCULATION
non-peak hours, which increases
the potential for and severity of
collisions between vehicles and
bicyclists or pedestrians.
3. Alternative Transportation
Modes. Traditional LOS policy
measures driver comfort and
convenience, which means that
considerations for pedestrians or
bicyclists using the same facility
are not always incorporated.
4. Physical Space. The goal of an
efficient transportation network
is to increase the capacity for
person-trips, not just vehicle-
trips. Maintaining a higher LOS
policy typically focuses on using
the public right-of-way or road
space to move automobiles
through the network instead of
people.
5. Air Quality and GHG. LOS
thresholds influence travel
speeds and may induce
vehicular travel in the case
where driving is made easier.
Cut-through traffic is an example
of induced travel in Diamond
Bar. Higher speeds and induced
vehicle travel can both result in
higher levels of air pollutant and
GHG emissions.
6. Community Character.
Achieving LOS thresholds may
require changes to the roadway,
such as road widening, that
can influence the character of
neighborhoods by changing the
building-to-street relationship, or
removing opportunities for green
infrastructure and wide sidewalks
alongside streets. Some of the
proposed mixed-use areas in the
General Plan have streets that
would need to have additional
pedestrian crossings, street
trees, pedestrian-scaled lighting
and other features to enable
them to be more comfortable
for pedestrians, rather than
widened to accommodate
additional traffic flow.
It is expected that decision-makers
and community members will use
the policy tradeoffs listed above
to make decisions about LOS
thresholds on specific roadways
should they road conditions change
during the implementation of this
General Plan.
Vehicle Miles Traveled
VMT is the State preferred
performance metric for
environmental analyses pursuant
to CEQA to describe the overall
amount of travel in the City based
on distance and is directly related
to fuel consumption, air pollution,
and GHG emissions. VMT is defined
as the total mileage traveled by
all vehicles. Although VMT relates
specifically to automobiles, it is
able to capture the effects of
development patterns such as
land use mix and density along
with transit, bike, and pedestrian
infrastructure improvements by
reflecting their impacts on vehicle
trip generation and trip lengths.
The City will use a combination of
LOS and VMT metrics to ensure the
efficient movement of people and
goods as well as reductions in GHG
emissions.
Efforts to reduce VMT may include
locating housing and jobs near
transit stations, implementing
transportation demand
CIRCULATION | Diamond Bar General Plan 20404-16
management (TDM) strategies
such as road or parking pricing,
commute trip reduction programs,
transit system improvements, or
providing facilities for modes of
transportation other than single
occupant vehicles. Introducing a
greater mix of land uses can also
reduce VMT in that residents may
have better access to resources
and opportunities such as
entertainment, shopping, and jobs,
thus reducing the length of their
trips.
TRANSPORTATION DEMAND MANAGEMENT (TDM)
TDM refers to a comprehensive
strategy to reduce driving and
resulting VMT by promoting
alternatives such as public transit,
carpooling, bicycling, walking,
and telecommuting. While some
TDM measures can be undertaken
by the City, such as investments
in facilities and programs to
encourage alternative modes of
transportation, other TDM measures
require collaboration with other
jurisdictions, for example with transit
providers to seek expanded service,
or with employers to encourage
flexible work schedules and the
provision of on-site childcare,
preferential carpool parking, and
subsidized transit passes.
INTELLIGENT TRANSPORTATION SYSTEMS
Intelligent Transportation Systems
(ITS) refers to a set of tools that
facilitates a connected, integrated
transportation system. Applications
of ITS includes adaptive traffic
prioritization signals aimed at
congestion management and
improving traffic flow, and the
collection and dissemination of
real-time travel information such
as transit arrivals or traffic incident
alerts. Other applications of ITS to
be considered as transportation
patterns change and emerging
technologies come online may
include connecting autonomous
vehicles and smart city integration.
SAFETY AND TRAFFIC CALMING
Steep grades, wide lanes, and
extra capacity on some roadways
in the City can lead to high vehicle
speeds. Traffic calming is a potential
method to discourage high vehicle
speeds and improve safety for all
road users, including vehicles, which
the City has already implemented
on local neighborhood streets
through its Neighborhood Traffic
Management Program. Traffic
calming has the added benefit of
potentially discouraging regional
cut-through traffic from SR-57 and
SR-60 through the City and related
vehicle congestion. Implementing
traffic calming strategies such as
roundabouts, corner bulb-outs,
speed cushions, surface textures,
raised pavement, road narrowing
and others, paying particular
attention to collision hotspots as
identified by Caltrans collision data
and City-level safety analyses, can
greatly improve safety for all road
users.
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GOALS & POLICIES
GOALS
CR-G-7 Ensure smooth traffic flows by maintaining or
improving traffic levels of service
(LOS) that balance operational
efficiency, technological and
economic feasibility, and safety.
CR-G-8 Encourage reduction in vehicle miles
traveled (VMT) as part of a strategy to
reduce greenhouse gas (GHG) emissions.
CR-G-9 Create and maintain programs for funding
transportation improvements,
with fair and equitable sharing of
transportation improvement costs.
CR-G-10 Discourage traffic from SR-57 and SR-60 from
using Diamond Bar roadways as
alternatives to the freeway.
POLICIES
LOS Standards
CR-P-12 Balance meeting LOS standards with the
need to reduce VMT through maintaining
and supporting multi-modal connectivity
such as transit, bicycling, walking, and
by encouraging infill development with a
pedestrian-friendly urban design character.
CR-P-13 Maintain a standard of LOS D during peak
hour conditions on all streets in the City’s
jurisdiction, with exceptions as noted below:
a. Brea Canyon Road south of Diamond
Bar Boulevard (LOS F)
b. Brea Canyon Road north of Diamond
Bar Boulevard (LOS E)
c. Grand Avenue west of Country View Dr
(LOS E)
d. Diamond Bar Boulevard at SR-60
Eastbound Ramps (LOS F).
CIRCULATION | Diamond Bar General Plan 20404-18
CR-P-14 Prioritize pedestrian movement and safety—
through wider sidewalks, more
frequent pedestrian crossings, sidewalk
bulbouts, median pedestrian refuges
etc.—rather than LOS in Community
Character Priority Areas, which are areas
designated for higher density mixed-use
development in the General Plan.
See Section 4.4 for more detailed policies
on bicycle and pedestrian
movement in mixed-use areas.
CR-P-15 Limit street right-of-way dimensions where
appropriate to maintain desired
neighborhood character. Consider
allowing narrower street rights-of-way
and pavement widths for local streets
in new residential subdivisions.
CR-P-16 Allow exceptions to LOS standards upon
findings by the City Council that
achieving the designated LOS would:
a. Be technologically or economically
infeasible; or
b. Compromise the City’s ability to support
other important policy priorities,
including but not limited to:
i. Promoting alternate modes
of transportation;
ii. Ensuring pedestrian, bicycle and
automobile safety, comfort,
and convenience;
iii. Reducing VMT and GHG
emissions; and
iv. Preserving and enhancing character
of the community.
CR-P-17 Maintain roadway design standards to
manage vehicle speeds and traffic
volumes, updating them as needed.
CR-P-18 Prioritize and phase improvements through
the City’s Capital Improvements Program
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GOALS & POLICIES
process as development proceeds,
given the extended time frame of
General Plan implementation.
CR-P-19 Develop a prioritized program to implement
measures to reduce traffic collisions at
collision hot spots. Continue to monitor
collision data for type, location, severity,
and cause and update the collision
reduction program as needed.
Adaptive Traffic Control (ATCS) and Intelligent Traffic
Systems (ITS)
CR-P-20 Implement measures such as additional
signal timing and synchronization, speed
limit regulations, and ITS techniques to
increase safety and reduce congestion.
Maintain a pavement management
system and maintenance program for all
public roadways throughout the City.
CR-P-21 On an ongoing basis, examine opportunities
to avoid delay, spillover, or cut-through
traffic onto Diamond Bar’s roadways
through techniques such as adaptive traffic
control systems along major corridors
and traffic calming measures along cut-
through routes that would reduce speeds
and discourage drivers from electing to
drive on them. Consider financial and
technological feasibility and community
priorities to determine whether and how
strategies should be implemented.
Safety
CR-P-22 Implement traffic calming measures to slow
traffic on local and collector residential
streets and prioritize these measures
over congestion management
where appropriate and feasible.
CR-P-23 Maintain the integrity of existing residential
areas and discourage cut-through traffic
by retaining cul-de-sacs and implementing
other traffic calming measures that
promote safe driving at speeds appropriate
to the surrounding neighborhood,
CIRCULATION | Diamond Bar General Plan 20404-20
particularly at Prospectors Road,
Chaparral Drive, Sunset Crossing Road,
Lycoming Street, and Washington Street.
Transportation Demand Management
CR-P-24 As opportunities arise, coordinate with local,
regional, and State agencies to encourage
and support programs that reduce vehicle
miles traveled, such as preferential carpool
and car share parking, parking pricing,
on-site childcare, flexible work schedules,
subsidized transit passes, and ridesharing.
CR-P-25 Encourage participation in transportation
demand programs, such as those
promoting walking, cycling, and transit,
through the use of City publications and
public displays in order to decrease
use of single occupancy vehicles.
Inter-Jurisdictional Coordination
CR-P-26 As opportunities arise, coordinate with other
jurisdictions, including neighboring cities,
Los Angeles County, San Bernardino
County, and Caltrans, on improvements
to street segments common to the City
of Diamond Bar and other jurisdictions.
CR-P-27 Encourage improvements to regional routes
and arterial streets to account for
environmental, aesthetic, and noise
concerns, as well as to provide adequate
buffers to adjacent land uses.
CR-P-28 As opportunities arise, coordinate with
Pomona Unified School District and City
of Chino Hills to ensure the timely design
and construction of secondary access
to Diamond Ranch High School that
would not substantially increase traffic in
surrounding residential neighborhoods.
CR-P-29 Solicit State and Federal funds to improve
area freeways and local streets.
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GOALS & POLICIES
4.4 PEDESTRIAN AND BICYCLE CIRCULATION
Non-motorized modes of
transportation are environmentally-
friendly alternatives to motor
vehicles that enhance both
personal and social well-being
through opportunities for
exercise and social interaction.
These alternatives to motorized
transportation are important parts
of a complete transportation system
that offers residents of Diamond Bar
a suite of options for moving around
their city. In addition to acting as
alternatives to single-occupant
vehicle travel, these modes of
travel provide many public access,
health, and economic benefits,
and are therefore recognized as
integral components of Diamond
Bar’s transportation system. Safe,
convenient, attractive, and well-
designed pedestrian and bicycle
facilities are essential if these modes
are to be properly accommodated
and encouraged.
PEDESTRIAN FACILITIES
Nearly everyone is a pedestrian.
Walking or use of a wheelchair is
part of almost every trip, whether it
is from the parking lot to a building
or from one’s home to a bus stop,
work, or store. The pedestrian
environment is thus a crucial part
of an accessible transportation
network, while also playing an
important role in the public realm
where attractive pedestrian
environments can spur activity.
Diamond Bar’s pedestrian network
consists of sidewalks and street
crossings as well as off-road paths
and trails. While most streets in
Diamond Bar have sidewalks, the
suburban layout with winding
roads and high-speed arterials with
narrow sidewalks and spread out
crossings can present a difficult
pedestrian environment. Factors
that affect walkability and the
pedestrian experience in the City at
large include:
• Direct, Fine-Grained Pedestrian
Networks. Walking is more
efficient and desirable as a
means of transportation if direct
pedestrian travel, rather than
circuitous routes, are available.
This is achieved through the
development of fine-grained
networks of pedestrian pathways
that allow for direct pedestrian
access to destinations.
• Sidewalk Continuity.
Communities are more walkable
if sidewalks do not end abruptly
and are present on the entire
segment and both sides of
a roadway. This is especially
important for the mobility-
impaired or those pushing small
children in strollers.
• Sidewalk Conditions. This refers
to the physical condition of
sidewalk surfaces. Sidewalks
that are broken or cracked can
deter walkability and pose a
safety hazard, particularly for the
mobility impaired, such as those
in wheel chairs and persons
using walkers or strollers.
CIRCULATION | Diamond Bar General Plan 20404-22
• Shading. People are more
inclined to walk in areas
where there is shade present,
particularly in Southern
California with its relatively warm
weather and limited rainfall as
compared to other locations.
Additionally, shade trees create
an aesthetic value that is
pleasing to the pedestrian.
• Grade. People are more
inclined to walk in areas that
are relatively flat or have limited
grade changes.
• Amenities. All else being equal,
people are more inclined to
walk in areas that are interesting
environments with shopping,
retail, restaurants, and other
similar uses. Pedestrian-friendly
amenities include street
furniture, attractive paving,
way-finding signage, enhanced
landscaping, and improved
lighting.
• Buffers. A more walkable
environment is one in which
there is some degree of
separation between the
pedestrian and the motorist.
This typically includes wider
sidewalks, street parking
and sidewalk bulb-outs at
intersections where feasible.
Crosswalks with appropriate
signage serve as an important
buffer as well.
BICYCLE FACILITIES
The City of Diamond Bar has made
a concerted effort to expand the
ease of alternative transportation
options for residents, recognizing
both health and environmental
benefits. This includes the
introduction of bicycle facilities
along roads such as Golden Springs
Drive and Brea Canyon Road.
However, opportunities still exist to
further expand and improve these
facilities. For example, bicycle lanes
on Grand Avenue in neighboring
Chino Hills to the east terminate
at the City limits despite having
sufficient right-of-way to continue.
Bicycle lanes on Golden Springs
Drive are discontinuous, with gaps
on a number of segments through
the City. Local neighborhood
streets feeding onto roads such
as Diamond Bar Boulevard and
Grand Avenue could benefit
from designated bicycle routes.
Finally, the standard of bicycle
infrastructure in California has
changed, skewing towards the
provision of protected infrastructure
where cyclists face higher vehicle
volumes and speeds.
The California Department of
Transportation’s (Caltrans) Highway
Design Manual (HDM) (Chapter
1000: Bikeway Planning and Design)
and California AB 1193 codify four
distinct classifications of bikeways.
Bikeways offer various levels of
separation from traffic based on
vehicle volumes and speed, among
other factors.
Diamond Bar General Plan 2040 | CIRCULATION 4-23
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Class I: Multi-Use Path
Class II: Bicycle Lane
Proposed Facilities
Class I: Multi-Use Path
Class II: Bicycle Lane
Class III: Bicycle Route
Class IV: Protected Bike Lane
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Source: Fehr & Peers 2019;
City of Diamond Bar, 2019; Dyett & Bhatia, 2019
Figure 4-2: Proposed Bicycle Network City of Diamond Bar
GENERAL PLAN UPDATEFigure 4-2 Proposed Bicyle Network
CIRCULATION | Diamond Bar General Plan 20404-24
Class I: Multi-Use Path
Class I Multi-Use Paths provide a separate right-of-way
and are designated for the exclusive use of people
riding bicycles and walking with minimal cross-flow
of vehicle traffic. Class I Bikeways offer opportunities
not provided by the road system by serving as both
recreational areas and/or desirable commuter routes.
Class II: Bicycle Lane
Class II Bicycle Lanes provide designated street
space for bicyclists, typically adjacent to the outer
vehicle travel lanes. Bike lanes include dedicated
lane markings, pavement legends, and signage. Bike
lanes may be enhanced with painted buffers between
vehicle lanes and/or parking, and green paint at
conflict zones (such as driveways or intersections), which
can be especially useful on streets with higher vehicle
traffic speeds or volumes.
Class III: Bicycle Route
Class III Bicycle Routes provide enhanced mixed-traffic
conditions for bicyclists through signage, striping, and/or
traffic calming treatments, and to provide continuity to
a bikeway network. Bike routes are typically designated
along gaps between bike trails or bike lanes, or along
low-volume, low-speed streets.
Class IV: Protected Bike Lane
Class IV Protected Bike Lanes, also referred to as cycle
tracks or separated bikeways, are bikeways for the
exclusive use of bicycles that are physically separated
from vehicle traffic. Types of separation may include,
but are not limited to, grade separation, flexible posts,
physical barriers, or on-street parking.
Figure 4-2 shows existing and planned bicycle facilities
in Diamond Bar. Bikeway classifications and existing
facilities of each type are described on the following
pages. The Circulation Chapter will be the primary
guide for bicycle planning in the City until such a time
as a more detailed and up-to-date bicycle master plan
is developed.
Diamond Bar General Plan 2040 | CIRCULATION
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GOALS & POLICIES
See Chapter 6: Public Facilities and Services for
additional policies regarding trails and recreational
facilities.
GOALS
CR-G-11 Expand and strengthen existing pedestrian
and cyclist network and facilities.
CR-G-12 Improve safety and accessibility for
pedestrians and cyclists.
POLICIES
Bicycle and Pedestrian Network
CR-P-30 Use Figure 4-2: Proposed Bicycle Network as
the overall guide for undertaking
bikeway and pedestrian improvements
in the community, with the Parks and
Recreation Master Plan providing a more
detailed implementation strategy.
CR-P-31 When updating the Parks and Recreation
Master Plan use community input and best
practices to identify bicycle infrastructure
needs such as gaps in the network, prioritize
facilities and improvements, and identify
funding for proposed facilities. Review
and update the plan as necessary.
CR-P-32 Promote pedestrian and bicycle
connectivity in existing residential
neighborhoods, utility easements,
and/or flood control channels,
including connections through cul-
de-sacs to other streets or community
facilities where feasible.
CR-P-33 Ensure that new development integrates
with Diamond Bar’s bicycle and
pedestrian networks by requiring
developers to provide sidewalks and
bicycle infrastructure on local streets.
CR-P-34 As opportunities arise, collaborate with
neighboring jurisdictions and colleges
such as Cal Poly Pomona and Mt. San
Antonio College to establish a safe
CIRCULATION | Diamond Bar General Plan 20404-26
and efficient bicycle route between
Diamond Bar and these institutions.
Design and Programs
CR-P-35 Develop bicycle and pedestrian facility
standards for pavement design, signage, and
roadway and intersection striping for each
functional roadway classification, so streets
are accessible by all users and modes.
CR-G-36 Where appropriate, plant street trees and
provide landscaping along major
pedestrian and bicycle routes to provide
shade and barriers between cyclists and
motorists, as well as enhance aesthetics.
CR-P-37 Ensure that secure and convenient bicycle
parking is available at major destinations
such as the Town Center, commercial
centers, transit stops, schools, parks, multi-
family housing, and large employers.
CR-P-38 If warranted by demand, study the feasibility
of implementing a bike share program
to connect neighborhoods and major
destinations, such as the Transit-Oriented,
Neighborhood, Town Center, and Community
Core Overlay mixed-use areas; local schools
and colleges; parks; and commercial centers.
Bicycle and Pedestrian Movement in Mixed Use Areas
CR-P-39 Ensure a safe environment for pedestrians
and cyclists while allowing for local traffic to
access freeways in the Neighborhood Mixed
Use area through the following strategies:
a. Widening sidewalks, providing planting
strips between sidewalks and streets
and providing pedestrian amenities
such as shade trees and street furniture
along Diamond Bar Boulevard;
b. Implementing traffic calming measures
such as reduced vehicle speeds,
striping and signange along
Diamond Bar Boulevard;
Diamond Bar General Plan 2040 | CIRCULATION
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GOALS & POLICIES
c. Buffering bike lanes along
Diamond Bar Boulevard;
d. Enhancing pedestrian crossings at the
intersection of Diamond Bar Boulevard
and Sunset Crossing Road, at Diamond
Bar Boulevard and Highland Valley
Road, and at Diamond Bar Boulevard
and the SR-60 on/off ramps; and
e. Incorporating multi-use pathways
internal to new development and
connecting to existing development.
CR-P-40 Provide for a vibrant Town Center that
encourages pedestrian activity and
comfort within the Town Center Mixed
Use area while accommodating through
traffic along Diamond Bar Boulevard
through the following strategies:
a. Establishing a new pedestrian-oriented
main street or pedestrian
pathway in the Town Center;
b. Enhancing the pedestrian experience
along Diamond Bar Boulevard within
the Town Center area with widened
sidewalks, shade trees, and pedestrian
amenities such as street furniture,
attractive paving, pedestrian-scaled
lighting, and landscape buffers;
c. Buffering bike lanes along
Diamond Bar Boulevard;
d. Improving crosswalks at the intersection
of Diamond Bar Boulevard and Palomino
Drive, at Diamond Bar Boulevard and
Golden Springs Drive, and where
Diamond Bar Boulevard intersects with
the driveway to the Town Center; and
e. Strengthening cyclist and pedestrian
connections between the Town
Center area and nearby schools to
provide safe and convenient routes
to the Town Center for students by
identifying barriers such as safety
hazards and gaps in the bicycle and
CIRCULATION | Diamond Bar General Plan 20404-28
pedestrian networks and implementing
improvements to address those barriers.
CR-P-41 Promote a fine-grained network of safe
pedestrian, bicycle, and vehicle connections
in the Transit Oriented Mixed-Use area,
emphasizing connectivity to the Metrolink
station through the following strategies:
a. Improving crosswalks along Brea Canyon
Road and Lemon Avenue;
b. Enhancing the pedestrian experience
along South Brea Canyon Road
within the Transit Oriented Mixed
Use area with widened sidewalks,
shade trees, and pedestrian
amenities such as street furniture,
attractive paving, and pedestrian-
scaled lighting, where feasible;
c. Providing high-visibility pedestrian and
bicycle connections to the
Metrolink station;
d. Incorporating multi-use pathways
internal to new development and
connecting to existing development; and
e. Studying the potential for shuttle,
bikeshare, and/or other linkages
to improve the convenience of
travel within the mixed-use area.
Safety
CR-P-42 Develop and implement programs in
collaboration with interested stakeholders
such as school districts, senior living
facilities, and community organizations
to encourage active transportation
among students and seniors while
ensuring student and senior safety.
CR-P-43 When planning capital improvement
programs, ensure that projects incorporate
measures that strengthen the protection
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GOALS & POLICIES
of cyclists in bike lanes by implementing
improvements such as increasing visibility
of lane markings and signage, increasing
bike lane widths, raising lanes, designing
safer intersection crossings and turns, and
buffering lanes from traffic wherever feasible,
prioritizing bicycle lanes along arterials.
CR-P-44 Enhance bicycle and pedestrian safety and
comfort where feasible
through means such as:
a. Introducing bicycle- and pedestrian-level
street lighting to improve safety at night;
b. Furnishing intersections with crosswalks on
all legs of the intersection;
c. Improving pedestrian safety with
intersection design features such as
improved signal timing, sidewalk bulb-
outs, pedestrian refuge islands with
“noses” that extend past the crosswalks,
advance vehicle stop bars, high visibility
crosswalk striping or decorative paving;
d. Improving bicycle safety with intersection
design features such as bicycle detection
and signalization, painted bike boxes,
and intersection crossing markings;
e. Widening sidewalks, providing planting
strips between sidewalks and streets and
providing pedestrian amenities such as
shade trees and street furniture; and
f. Implementing traffic calming measures to
reduce vehicle speeds and congestion.
CR-P-45 Routinely review pedestrian and cyclist
collision data for type, location,
severity, and cause, and develop
strategies to prevent these collisions.
CIRCULATION | Diamond Bar General Plan 20404-30
4.5 PUBLIC TRANSPORTATION
Transit service can provide
an alternative to automobile
travel and is a critical mode of
transportation for those who
cannot drive (such as the elderly,
youth, or disabled) or do not
have access to a vehicle. Limited
fixed-route service is provided
within Diamond Bar, primarily
along major arterials, operated
by Foothill Transit and supported
by two Caltrans park-and-ride lots
on Diamond Bar Boulevard (see
Figure 4-3). Paratransit service is
provided to qualifying residents by
Access Services, a curb-to-curb
paratransit program serving Los
Angeles County residents unable
to use regular bus service, and by
the City’s Diamond Ride program,
which is a subsidized cab program
designed to supplement travel
means for persons with disabilities
and those age 60 and older
residing in Diamond Bar. Diamond
Bar residents are also served by
the Metrolink Riverside Line along
the northwestern boundary of the
City. This line runs from Downtown
Riverside to Union Station in
Downtown Los Angeles and
provides service Monday to Friday.
Given that the majority of Diamond
Bar is of a suburban, low-density
character, expanding public transit
routes within Diamond Bar would
likely be an inefficient method of
attracting greater transit ridership.
Other methods of attracting
ridership could include focusing
on providing high-quality service
between employment centers and
mixed-use destinations along the
spines of the City, supplemented
with features such as park-n-rides
and pedestrian and bicycle
infrastructure to create multi-
modal transportation nodes, and
coordinating with transit providers
to promote bus user satisfaction
through strategies such as providing
real-time arrival times at stops and
through mobile and web-based
applications.
This Chapter’s policies also support
Metrolink ridership by improving
bus, bicycle, and pedestrian
connections to the station (refer
to Figure 4-2: Proposed Bicycle
Network and policies in the Chapter
3, Community Character and
Placemaking and policies below),
and by introducing mixed-use
development around the station.
Coordination with Metrolink and
Union Pacific Railroad (UPRR) to
provide more frequent service to
increase Metrolink’s convenience
and ridership amongst Diamond
Bar residents represents another
potential way to increase transit
ridership and satisfaction.
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Figure 4-3: Transit Corridors City of Diamond Bar
GENERAL PLAN UPDATE
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
Highways
Ramps
Major Roads
Local Roads
Railroads
Park and Ride LotBus Routes
Foothill Transit
Figure 4-3 Transit Lines and Facilities
CIRCULATION | Diamond Bar General Plan 20404-32
GOALS
CR-G-13. Support the availability, efficiency, and
effectiveness of public transit service.
POLICIES
CR-P-46 Where feasible, integrate transit nodes and
connections with adjacent existing
and proposed developments and
destinations—such as employment centers,
commercial centers, major attractions,
and public pedestrian spaces—to make
them more accessible to transit users.
CR-P-47 As opportunities arise, coordinate with
Foothill Transit, Metrolink, and other
transit providers to incorporate real-
time information systems at transit stops
so that passengers will know when
their vehicle is expected to arrive.
CR-P-48 As opportunities arise, work with Foothill
Transit to maintain and improve bus
stops and shelters, as well as identify
areas where service can be improved
or expanded to increase system use.
CR-P-49 Create additional pedestrian, bus, and
bikeway connections to the Metrolink
station to address first- and last-mile
(FMLM) connectivity and make it
easier to travel to between the station
and surrounding neighborhoods.
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GOALS & POLICIES
CR-P-50 As opportunities arise, coordinate with
Metrolink and Union Pacific Railroad
(UPRR) to provide more frequent service
at the City of Industry station, including
service for shorter trips, to increase
the convenience and use of transit.
CR-P-51 Support, where feasible, privately funded
local transit systems that are accessible
for seniors, youths, and individuals with
disabilities, to ensure that all community
members have the ability to travel
while decreasing congestion.
CR-P-52 In areas or on routes between destinations
that have been determined to be
infeasible for public transit providers to
serve, explore the use of programs that
subsidize the use of TNCs, alternative
transit services, or the City’s Diamond Ride
program, particularly for populations with
special needs, such as seniors, youths,
or persons with disabilities, until such a
time as mass transit becomes feasible.
CIRCULATION | Diamond Bar General Plan 20404-34
4.6 PARKING
Parking goals and policies reflect
both the necessity of providing
for adequate and appropriately
located vehicle and bicycle parking
in existing and new development,
and priorities related to safety,
urban design, and transportation
demand management. More
flexible parking standards for
projects that provide VMT reduction
and TDM measures such as shared
parking lots, subsidized transit
passes, or carshare help to reduce,
development costs, remove
pedestrian barriers, and create
a more pedestrian-friendly and
attractive built environment. Parking
requirements are implemented
primarily through the City’s Zoning
Ordinance.
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GOALS & POLICIES
GOALS
CR-G-14. Provide adequate parking for all land use
types, while balancing this against the
need to promote walkable, mixed-use
districts and neighborhoods in targeted
areas, and promoting ride-sharing and
alternative transportation modes.
POLICIES
CR-P-53 Update parking standards in the
Development Code to ensure that
they are reflective of the community’s
needs, using current data on parking
demand and taking into consideration
demographics and access to
alternative modes of transportation.
CR-P-54 Incorporate criteria in the Development
Code to allow reductions in parking
requirements in exchange for
VMT reduction measures.
CR-P-55 Establish common bicycle parking
requirements for appropriate uses—
including multi-family residential and
office—in the Development Code.
CR-P-56 Establish requirements to provide dedicated
parking and charging stations
for electric vehicles.
CR-P-57 Develop incentives to encourage
carpooling, such as preferential parking
for high-occupancy vehicles.
CR-P-58 Encourage public schools to improve
parking and loading facilities to
minimize congestion and delays
on the local circulation system.
CR-P-59 As opportunities arise, work with Caltrans to
evaluate existing Caltrans-operated
park-n-ride facilities within the City and
expand the facilities where necessary.
CIRCULATION | Diamond Bar General Plan 20404-36
4.7 EMERGENCY ACCESS
Adequate emergency vehicle
access is crucial in terms of
protecting the safety and well-
being of Diamond Bar’s residents.
Emergency access to individual
buildings is regulated by the
adopted California Fire Code.
Emergency access can also be
facilitated through roadway design
standards that allow for emergency
vehicle movement, as well as the
identification of evacuation routes
should residents need to leave in
the event of a disaster. See Chapter
7: Public Safety regarding goals
and policies related to emergency
access.
4.8 GOODS MOVEMENT
Goods movement plays an
important role in both the
circulation network and the
economy of a city such as Diamond
Bar. Often, it can be difficult
to balance accommodating
trucks and other vehicles without
impeding other modes or the well-
being of residents of the City. Given
its location at the confluence of
two highways, Diamond Bar must
continue to direct goods movement
to appropriate locations in its
transportation network.
Due to the operational
characteristics of trucks and
railroads, goods movement can
be incompatible with some
land uses and other users of the
transportation system. At the
State level, the California Public
Utilities Commission (CPUC) has
jurisdiction over State-level safety
regulations for common carriers
(including trucks and rail). The
Surface Transportation Assistance
Act (STAA) of 1982 also defines a
network of highways as truck routes.
Large trucks are allowed to operate
on these routes. Goods movement
into and through Diamond Bar is
currently accommodated by STAA-
designated SR-57 and SR-60. At the
local level, the City of Diamond
Bar has a designated truck route
network that connects to these
STAA-designates routes, as shown
on Figure 4-4: Goods Movement.
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CO PLEYDRBRIDGEGATEDRVALLEYVISTADRROCKRIVERRDCity-Designated Truck Routes
STAA-Designated Truck Routes
Highways
Ramps
Major Roads
Local Roads
Railroads
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Source: Fehr & Peers, 2019;
City of Diamond Bar, 2019; Dyett & Bhatia, 2019Riv ersideMetrolinkLineFigure 4-4: Goods Movement City of Diamond Bar
GENERAL PLAN UPDATEFigure 4-4 Goods Movement
CIRCULATION | Diamond Bar General Plan 20404-38
GOALS
CR-G-15 Minimize quality of life impacts of goods
movement in and through the City while
facilitating the movement of goods
destined for locations within the City.
CR-G-16 Facilitate safe and efficient movement,
loading, and unloading (i.e.
pick-up and delivery) of goods at
destinations within the City.
CR-G-17 Advocate for regional transportation
solutions that are equitable in the
distribution of goods movement traffic.
POLICIES
Truck Routes
CR-P-60 Use Figure 4-4: Goods Movement as the
guide for designating truck
routes in the City.
CR-P-61 Review designated truck routes of adjoining
jurisdictions and coordinate as needed
to ensure continuity of facilities (e.g. Los
Angeles County, City of Industry, City
of Pomona, and City of Chino Hills).
CR-P-62 Maintain truck routes with signage between
industrial areas and freeway interchanges
to discourage truck travel through
residential neighborhoods, and
provide truck route information to
truck routing software providers.
CR-P-63 Develop design guidelines for designated
truck routes, including proper
turning radii at intersections.
CR-P-64 Continue prohibiting trucks heavier than 5
tons from operating on designated
residential streets, except for
emergency, maintenance, residential
moving trucks, and transit vehicles,
to maintain pavement integrity.
Diamond Bar General Plan 2040 | CIRCULATION
4.0
4-39
GOALS & POLICIES
CR-P-65 Periodically review collision data for type,
location, severity, and cause. Develop
countermeasures for sites with
recurrent truck-involved collisions.
Delivery and Loading
CR-P-66 Encourage off-peak delivery of goods in
non-residential areas through a
combination of incentives and restrictions.
CR-P-67 Ensure that trucks do not interfere with
cyclist or pedestrian activity by:
a. Incorporating off-street or buffered bike
lanes and walking paths where
truck routes overlap with bicycle
routes or streets with heavy
pedestrian traffic; and
b. Designing driveways and curb cuts to
avoid maneuvering on sidewalks or in
street traffic, while also facilitating the
safe and efficient movement of trucks.
CR-P-68 Minimize noise impacts from trucks by
enforcing delivery restrictions on
certain routes and/or during certain
times of day in order to minimize noise
impacts on sensitive receptors.
CR-P-69 Incorporate provisions for loading/unloading
during the development review process.
Analysis of assumed loading/unloading
activity should be reviewed by both the
Planning and Public Works departments to
ensure that the location and dimensions
of loading location(s) support the planned
use and minimize impacts to vehicular
traffic, pedestrians, and bicyclists.
CR-P-70 Review and establish standards for off-street
loading spaces for multi-family
developments; consider short term
loading areas or a centralized
delivery area for residential complexes
and commercial areas.
CIRCULATION | Diamond Bar General Plan 20404-40
CR-P-71 Investigate the use of “big data” to better
understand truck flows within and through
the City, such as type of trucks, origin
and destination of these trucks, role of
different facilities in the City serving origin/
destinations in the City, and local serving
versus pass-through truck movements in
Diamond Bar, and use this information to
ensure that truck routes are designated
del and that safety, congestion, and
maintenance issues along heavily
trafficked routes are addressed.
Coordination and Clean Vehicles
CR-P-72 Continue to support regional solutions to
long distance goods movement, but
not to the detriment of the quality
of life of Diamond Bar residents.
CR-P-73 Advocate for clean truck technology or
smaller vehicles with lower emission rates.
For the Diamond Bar community,
local natural and cultural
resources play a major role in
making the City a unique and
desirable place to live. When
asked what they love about
their city, Diamond Bar residents
highlight its open spaces and
the diversity of plants and
wildlife that inhabit those areas.
RESOURCE
CONSERVATION 5.0
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-2
5.1 INTRODUCTION
Maintaining these and other
important resources such as
water and air quality is key to
ensuring both that the community
remains livable and the ecosystem
remains healthy, particularly in the
increasingly urbanized Southern
California region. Additionally,
in a young city like Diamond
Bar, identifying and highlighting
cultural resources will play a part
in establishing its identity. This
Resource Conservation Chapter
provides policies to guide the
City’s stewardship of its resources,
ensuring the conservation and
enhancement of open spaces,
biological resources, water and air
quality, and cultural resources.
RELATIONSHIP TO STATE LAW
California Government Code
sections 65302(d)(1) and 65302(e)
require cities to adopt conservation
and open space elements as
part of their general plans. A
conservation element is required
to provide guidance for the
conservation, development, and
utilization of natural resources,
including water quality and
hydraulic force, forests, soils, rivers
and other waters, harbors, fisheries,
wildlife, minerals, and others as
applicable to each jurisdiction. An
open space element is intended
to ensure that cities and counties
recognize that open space land is a
limited and valuable resource and
prepare and carry out open space
plans that guide the comprehensive
long-range preservation and
conservation of open space land.
The Resource Conservation Chapter
is a combination of these two
required elements, as several of
the issues addressed under each
topic are closely related. Relevant
resources in Diamond Bar discussed
in this chapter include open
space, biological resources, water
resources, air quality, and cultural
resources.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-3
RESOURCE CONSERVATION 5.0
RELATIONSHIP TO OTHER ELEMENTS
This chapter is closely related
to Chapter 2, Land Use and
Economic Development, Chapter
4, Circulation, Chapter 6, Public
Facilities and Services, and
Chapter 8, Community Health
and Sustainability. Chapter 2
establishes the Land Use Diagram
and designates allowable uses
throughout the Planning Area,
including those that identify lands
to be preserved as open space. It
also establishes various policies for
development to preserve the City’s
hillsides for the purposes of safety
and maintaining Diamond Bar’s
visual character. Chapter 4 lays
out a transportation network and
corresponding policies intended
to reduce vehicle miles traveled
and related air pollutant emissions.
Chapter 6 includes a discussion on
parks and recreation, including
recreational open space; water
supply and demand, which are tied
to water quality and hydrology;
and wastewater and stormwater
facilities, which also relate to
water quality. Finally, Chapter 8
includes some discussion related
to environmental justice, including
air quality, as it pertains to public
health; it also considers impacts
to natural resources as a result of
greenhouse gas (GHG) emissions.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-4
Open space is defined as any parcel or area of land or water that is
essentially unimproved and devoted to open space use. Such uses
include the preservation of natural resources, the managed production
of resources (such as agriculture or forestry), outdoor recreation, the
protection of public health and safety, support of the mission of military
installations, and the protection of tribal cultural resources (California
Government Code Sections 51075 and 65560). Unimproved land that is
designated for other uses is considered vacant land rather than open
space but may become open space if it is dedicated, acquired by a
public entity, or otherwise preserved in perpetuity. Dedicated open
spaces are designated on the General Plan Land Use Diagram with the
Open Space land use classification.
5.2 OPEN SPACE
OPEN SPACE INVENTORY
The open areas within the City are
integral to the creation of a sense
of place, its health, and its safety,
contributing to its countryside
atmosphere, providing opportunities
for outdoor recreation for all ages,
and supporting ecological health
and hazard mitigation. Ensuring
that areas treasured for their open
space values are preserved is a
priority for Diamond Bar community
members.
Figure 5-1 shows the Planning Area’s
open space network as of 2019,
including designated open spaces,
parks, and the Diamond Bar Golf
Course, which, while developed,
serves a number of open space
functions. The figure also shows the
Significant Ecological Area in the
SOI.
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION 5-5
Figure 5-1 Open Space Network
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Heritage
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Silver Tip
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Paul C
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Diamond
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Longview
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Stardust
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Golf Course
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City Owned Designated Open Space
Privately Owned Park/Recreation Area
Designated Privately Owned Open Space
Park
Golf Course
Highways
Ramps
Railroads
Major Roads
Minor Roads
City of Diamond Bar
Sphere of Influence/SEA 15
County Boundary
0 0.75 1.50.375
MILES
Figure 5-1: Open Space Network City of Diamond Bar
GENERAL PLAN UPDATE
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-6
PRESERVATION
Though much of the City is already
developed, opportunities remain
for the preservation of open space
in the future, whether through
public acquisition or dedication
by property owners. As areawide
plans are proposed and developed,
they can identify areas that serve
important ecological functions or
provide important connections
to regional wildlife corridors and
cluster development away from
those areas. Future projects can
be designed to incorporate open
spaces as buffers to help transition
between different types of uses,
provide ecosystem services such
as stormwater control and habitat
protection, and create passive
recreation opportunities and
connections to the trail system.
The development of public parks
in the future can provide similar
opportunities. Additionally,
topography within the City means
that many vacant areas may not
developable due to safety and soil
stability reasons or the potential
for impacts to the visual integrity
of the City’s hillsides. Over time,
these areas can be identified, and
the City can explore options to
designate them as permanent open
space.
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
5.0
5-7
GOALS & POLICIES
OPEN SPACE
See Chapter 2: Land Use and Economic Development
for policies regarding the designation of open space
land. See Chapter 5: Public Facilities and Services for
policies related to parks and recreational facilities.
GOALS
RC-G-1 Create and maintain a balanced open
space system that will preserve scenic
beauty and community identity,
protect important biological resources,
provide open space for outdoor
recreation and the enjoyment of
nature, conserve natural resources,
and ensure public health and safety.
RC-G-2 Seek to link the various elements of the
open space network through the
development of an integrated
system of trails and greenways.
RC-G-3 Preserve to the extent possible open space
ridgelines, hilltops, and prominent slopes for
aesthetic, biological and natural resource
conservation, and safety purposes.
POLICIES
RC-P-1 As opportunities arise, obtain and designate
open space land through
acquisition techniques such as:
a. Incorporating open space and
recreational areas into the design
of new development projects,
preserving and enhancing as open
space significant stands of vegetation,
natural landforms, and any areas
of special ecological significance
through site design approaches such as
clustering and ecological planning.
b. Allowing clustering or transferring of all
or part of the development potential of
a site to a portion of the site to preserve
significant environmental resources
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-8
such as natural and native habitats
(oak woodland, coastal sage
scrub, etc.), natural creeks, artesian
springs, vernal pools, seeps, riverines,
wetlands, riparian habitats, wildlife
corridors and linkages, and natural
geological features within proposed
developments as open space.
c. Allowing for acquisition of open space
lands through the entitlement process
and the transfer of densities among
land uses of like designation.
d. Collaborating with land trusts and
other conservation groups to acquire
open space land through, but not
limited to, conservation easements.
RC-P-2 As future parks are developed, incorporate
existing natural open space, existing
water resources and mature vegetation
to provide for passive recreation
opportunities and wildlife habitats.
RC-P-3 A decision to rescind, terminate, abandon,
remove, or modify an open space deed
restriction, map restriction or Open Space
land use designation must be preceded
by both a finding by the City Council that
the decision confers a significant benefit
on the City and a favorable vote of the
electorate at a regular or special election.
RC-P-4 Maintain an inventory of open lands that
were set aside for open space uses
as part of developments approved
prior to City incorporation, and require
verification as to the existence of any
potential open space restrictions previously
approved on a subject property prior to
approving development proposals.
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
5.0
5-9
GOALS & POLICIES
RC-P-5 Link parks, open spaces, and regional hiking
trails with a trail network where feasible,
acknowledging topographical constraints
and other barriers. Incorporate existing trails
and bicycle and pedestrian infrastructure,
working with willing landowners to prioritize
land acquisition where necessary. Where
possible, incorporate landscaping and
enhance natural features to create
greenways along the trail network.
RC-P-6 Update, as appropriate, standards for
planning, design, management,
and maintenance of trails and
pathways within parks, preserves,
open space, and rights-of-way.
RC-P-7 Minimize visual and environmental impacts
to ridgelines, hilltops, and slopes through
regulations that minimize grading,
ensure that development conforms
to natural topography, and maximize
safety, correlating development
intensity with the steepness of terrain.
Landform grading criteria and maximum
allowable densities shall be based
upon the slope density formula as set
forth in the Development Code.
RC-P-8 To the extent feasible, support and
cooperate with the efforts of other
jurisdictions and conservation organizations
to protect prominent ridges, slopes,
and hilltops in and adjacent to the
City and its Sphere of Influence.
Such features include, but are not limited
to, areas identified by Los Angeles County
as Significant Ecological Areas; Tonner
Canyon; the hills within Tres Hermanos
Ranch; and the hillsides along SR-57,
between Diamond Bar and Brea.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-10
5.4 BIOLOGICAL RESOURCES
VEGETATION COMMUNITIES
Although Diamond Bar is primarily
developed as a residential
community, vegetated habitat types
have a large presence within the
Planning Area’s hilly terrain. The
following vegetation communities
have been identified in the Planning
Area. This inventory is based on field
reconnaissance undertaken for the
General Plan process and review
of aerial imagery in 2016, as well as
input from the community; it was
determined at a broad, citywide
scale and is thus for guidance
purposes only. For a more detailed
understanding of conditions
on the ground, particularly as
conditions change over time, site-
specific study would be required.
Examples of situations when such
studies should be undertaken
include development proposals,
trail planning, and mitigation
bank planning. The vegetation
communities within the Planning
Area are mapped in Figure 5-2.
Venturan Coastal Sage Scrub
Venturan coastal sage scrub
(VCSS) is a form of coastal sage
scrub found in the coastal and
cismontane region of Southern
California and Baja California.
It is composed of low, soft-
woody subshrubs on dry slopes
below 3,000 feet. The dominant
characteristic species found in VCSS
within the City include California
sagebrush (Artemisia californica),
California buckwheat (Eriogonum
fasciculatum), and black and white
sage (Salvia melifera and Salvia
apiana). A dominance of California
buckwheat is present within some
of the VCSS communities, while
California sagebrush is the dominant
species in other areas. Other species
present within this vegetation
community include lemonadeberry
(Rhus integrifolia), brittlebush
(Encelia farinosa), and coastal
prickly pear (Opuntia littoralis).
The understory is dominated by
non-native grasses such as brome
(Bromus spp.) and wild oats (Avena
spp.). Where non-native grasses
dominate the VCSS communities
at greater than 50 percent, the
community is categorized as
disturbed VCSS. VCSS commonly
occurs on south-facing slopes
throughout the Planning Area. The
California Department of Fish and
Wildlife (CDFW) considers VCSS to
be a Sensitive Natural Community
(the characteristics of Sensitive
Natural Communities are described
later in this chapter).
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION 5-11
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Oak Woodland
Walnut Woodland
Sycamore Alluvial Woodland
Non-Native Woodland
Non-Native Grassland
Non-Native Riparian
Southern Willow Scrub
Venturan Coastal Sage Scrub
Disturbed Venturan Coastal Sage Scrub
Disturbed
Diamond Bar Golf Course
Developed
City of Diamond Bar
Sphere of Influence
0 0.75 1.50.375
MILES
Source: City of Diamond Bar 2019;
ESA PCR, 2016; Dyett & Bhatia, 2019 RiversideMetrolinkLineFigure 5-2: Natural Communities C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATE
Due to the scale of the mapping effort the refinement of the
delineation of coast live oak woodland and walnut woodland was
based on the slope face compass direction (north and east facing
for coast live oak woodland and south and west facing for walnut
woodland) and is subject to site-specific studies for individual
projects.
Figure 5-2 Natural Communities
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-12
Non-Native Grassland
Non-native grassland consists of
dense to sparse annual grasses less
than three feet high. Within the City,
this community is dominated by
bromes, oats, tocalote (Centaurea
melitensis), Russian thistle (Salsola
tragus), Mediterranean mustard
(Hirschfeldia incana), and telegraph
weed (Heterotheca grandiflora).
Other broadleaf weeds may also
be present. Non-native grassland is
largely located in the northeastern
corner of the City, due to a historic
presence of agricultural uses, as
well as in small parcels throughout
the City, often in areas that have
been cleared for fire control.
Sycamore Alluvial Woodland
Southern alluvial woodland is
located along braided channels
of intermittent streams, consisting
of open to moderately closed
winter-deciduous trees and
dominated by western sycamore
(Platanus racemosa). Blue
elderberry (Sambucus nigra) is also
a characteristic species. Within
the City, this habitat is composed
largely of western sycamore, with
blue elderberry and coast live oak
(Quercus agrifolia) interspersed
throughout. A small patch of
sycamore alluvial woodland is
located in upper Tonner Canyon.
Southern Willow Scrub
Southern willow scrub is a
deciduous, riparian community
dominated by dense thickets of
one or more willow tree species
and various other scattered shrubs
and larger emergent trees. Within
City boundaries, this community
consists mainly of arroyo willow
(Salix lasiolepis). Much of this
habitat within the City is between
6 and 15 feet in height and varies
in density, from relatively open
to impenetrable. Southern willow
scrub is found along Brea Canyon
Creek downstream of residential
development, along Tonner Canyon
Creek within the SOI, and along a
tributary of Tonner Canyon Creek
above Arnold Reservoir. Southern
willow scrub is another vegetation
community considered by the
CDFW to be a Sensitive Natural
Community.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-13
RESOURCE CONSERVATION 5.0
Coast Live Oak Woodland
Coast live oak woodland is
dominated solely by coast live
oak trees, which can reach
approximately 30 to 75 feet in
height, and occur generally in
shaded ravines on north-facing
slopes. This community often
has limited shrub cover with an
understory of ripgut grass (Bromus
diandrus). Within the City, the
dominant plant species is coast
live oak, with limited shrubs such
as toyon (Heteromeles arbutifolia)
and laurel sumac (Malosma laurina)
and an understory of mixed grasses,
predominately brome and oat.
Although the coast live oak is the
dominant tree species, coast live
oak woodland, as defined, is limited
to the northeastern region of the
City and the SOI, generally on
north-facing slopes.
California Walnut Woodland
California walnut woodland is
similar to coast live oak woodland
but is dominated by Southern
California black walnut (Juglans
californica); however, coast live oak
is a common species of this habitat.
Within the City, the dominance of
coast live oak varies throughout
this habitat but is largely present
throughout. Other species present
within this habitat include toyon,
laurel sumac, blue elderberry,
and an understory of non-native
grasses such as brome and oat.
California walnut woodland is
dispersed throughout much of the
City, generally occurring on north-
facing slopes. The CDFW considers
California walnut woodland to be a
Sensitive Natural Community.
Mixed Plant Communities
In cases where two or more
vegetation types are highly
intermixed, they have been
mapped as one mixed plant
community. Within the study
area these occur as: 1) California
walnut woodland/coast live oak
woodland, where California walnut
trees and coast live oak trees grow
in proximity with one another and
often have overlapping canopies;
and 2) California walnut woodland/
coast live oak woodland/Venturan
coastal sage scrub, where
California walnuts and coast live
oaks grow together in small copses
with Venturan coastal sage scrub
being found in between.
Other Land Cover Types
Non-Native Riparian
Non-native riparian consists of
densely vegetated riparian thickets
heavily dominated by invasive
plant species. Within the City,
this community consists largely of
Mexican fan palm (Washingtonia
robusta), Brazilian pepper tree
(Schinus terebinthifolius), and
eucalyptus (Eucalyptus sp.). Tree of
heaven (Ailanthus altissima) and
ornamental pines (Pinus sp.) also
occur within this community. There
is some presence of arroyo willow
and coast live oak, but natives
such as these make up less than 25
percent of the vegetation within
this community. Non-native riparian
habitat is located in a single patch
that runs along the south side of
SR-60 in the northern portion of the
City.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-14
Developed
Developed/urban areas have
been physically altered to the
point where they can no longer
support native vegetation. The
land cover type includes areas
with permanent or semi-permanent
structures, pavement or other
hardscape, and landscaped areas
that require irrigation. Developed
land constitutes nearly two-thirds of
the land within the City. It includes
businesses, residences, schools,
parks, highways and other roads,
sidewalks, and irrigated landscapes.
Within the areas called out as
developed habitat, there may be
some oak, walnut trees, or other
small pockets of native habit.
Disturbed
Disturbed areas have been
physically altered by previous
human activity and are no longer
able to support a recognizable
native or naturalized vegetation
association. The soil is often highly
compacted or frequently disturbed.
Disturbed habitat within the City
has shown evidence of discing or
high compaction. Only two small
portions within the northern region
of City were mapped as disturbed;
both areas are along roads and
adjacent to businesses.
Non-Native Woodland
Non-native woodland typically
consists of planted, non-native
trees, often characterized by
eucalyptus. Within the City,
non-native woodland consists of
Brazilian pepper trees, ornamental
pines, eucalyptus, and acacia
(Acacia sp.), among others. This
habitat is located in the southern
portion of the City and the SOI.
SPECIAL STATUS SPECIES AND HABITATS
Special-Status Plant Species
Special-status species are those
plants and animals that, because
of their acknowledged rarity or
vulnerability to various causes of
habitat loss or population decline,
are recognized in some fashion by
federal, State, or other agencies as
deserving special consideration.
According to the California Natural
Diversity Database (CNDDB), as of
2019, no special-status plant species
have been recorded within the City.
Several sensitive plant species have
been reported as recorded near
the City, including within the SOI,
as shown in Figure 5-3; however,
the majority of these species are
not expected to be present within
City limits for one or both of the
following reasons: suitable habitat
to support the species is not present
within the City; or the species
occurrences are highly localized
some distance from the City. These
plant species are described in Table
5-1.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-15
RESOURCE CONSERVATION 5.0
Table 5-1: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Scientific Name Common Name CNPS Listing Status
Preferred Habitat Records
Angiosperms
(Dicotyledons)
Asteraceae Sunflower Family
Microseris douglasii
var. platycarpha
Small-flowered
microseris
4.2 Cismontane woodland,
coastal scrub, valley
and foothill grassland/
clay.
Recorded in study area
south of Diamond Ranch
High School.
Senecio aphanactis Rayless ragwort 2B.2 Cismontane woodland,
coastal scrub, drying
alkaline flats.
Puddingstone Dam
(1932); moderate
potential where habitat
occurs.
Pseudognaphalium
leucocepalum
White rabbiy-
tobacco
2B.2 Sandy wash habitats Not recorded from the
Puente Hills; low potential
in study area.
Symphyotrichum
defoliatum
San Bernardino
aster
1B.2 Low potential to occur
in moist habitats.
Recorded from study
area vicinity, but possibly
extirpated.
Brassicaceae Mustard Family
Lepidium virginicum
var. robinsonii
Robinson’s pepper
grass
4.3 Chaparral and coastal
scrub.
Recorded in the Puente
Hills and within the study
area
Convolvulaceae Morning-Glory
Family
Convolvulus simulans small-flowered
morning glory
4.2 Coastal scrub, valley
and foothill grassland/
clay, serpentine seeps.
Moderate potential
where habitat occurs.
Crassulaceae Stonecrop Family
Dudleya multicaulis Many-stemmed
dudleya
1B.2 California plant
communities including
sage scrub, valley
and foothill grassland;
heavy clay soils or rock
outcrops.
Bonelli Regional Co. Park
(1987 and 1982); recorded
on Way Hill (1987);
Many CNDDB records
throughout the area;
high potential to occur in
study area.
Fabaceae Legume Family
Astragalus
brauntonii1
Braunton’s milk-
vetch
1B.1 Sage scrub, chaparral,
valley and foothill
grassland, closed
cone coniferous forest;
limestone endemic,
carbonate soils, recent
burns and disturbed
areas.
Recorded in San Gabriel
Mountain foothills to the
north and the Santa Ana
Mountain foothills to the
south; moderate potential
to occur in study area.
Quercus engelmannii Engelmann oak 4.2 Chaparral, cismontane
woodland, riparian
woodland, valley and
foothill grassland.
Recorded in the Chino
and Puente Hills;
moderate potential to
occur in study area.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-16
Table 5-1: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Scientific Name Common Name CNPS Listing Status
Preferred Habitat Records
Angiosperms
(Dicotyledons)
Hydrophyllaceae Waterleaf Family
Phacelia hubbyi Hubby’s phacelia 4.2 Sage scrub and
chaparral
Recorded in the Puente
Hills and west Pomona
hillsides; high potential to
occur in the study area.
Juglandaceae Walnut Family
Juglans californica Southern
California black
walnut
4.2 Sage scrub, chaparral,
cismontane woodland;
often in association with
oaks/oak woodland;
frequently found on
steep hillsides with
northern exposures;
deep alluvial soils.
Occurs throughout much
of the study area.
Liliaceae Lily Family
Brodiaea filifolia Thread-leaved
brodiaea
1B.1 Sage scrub, valley/
foothill grassland,
cismontane woodland;
vernal pools (clay soils).
Recorded from the San
Gabriel Mountains to
the north and Santiago
Hills to the southeast; low
potential to occur in the
study area.
Calochortus
catalinae
Catalina mariposa
lily
4.2 Openings in chaparral,
valley and foothill
grassland, cismontane
woodland; heavy soils.
Recorded within the study
area within openings in
shrublands and scrub.
Calochortus clavatus
var. gracilis
Slender mariposa
lily
1B.2 Chaparral, especially
in foothill canyons.;
generally found in
shade.
Low potential where
habitat occurs.
Calochortus
plummerae
Plummer's
mariposa lily
4.2 Sage scrub, valley
and foothill grassland,
yellow pine forest; dry,
rocky or sandy sites,
granitic or alluvial soil;
to 4,800 feet.
Potentially present in the
study area.
Calochortus weedii
var. intermedius
Intermediate
mariposa lily
1B.2 Chaparral, coastal
scrub, valley and
foothill grasslands.
Recorded in study area
and at Elephant Hill (1991)
in Pomona.
Orchidaceae Orchid Family
Piperia cooperi Cooper’s rein-
orchid
4.2 Scrub, chaparral and
oak/walnut woodlands
Not recorded in the
Puente Hills, but is
recorded in the Santa
Ana River Canyon to the
south; low potential to
occur in the study area.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-17
RESOURCE CONSERVATION 5.0
Table 5-1: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Scientific Name Common Name CNPS Listing Status
Preferred Habitat Records
Angiosperms
(Dicotyledons)
Polygalaceae Milkwort Family
Polygala cornuta var.
fishiae
Fish’s milkwort 4.3 Oak/walnut woodlands
and chaparral
Recorded in Chino Hills
State Park to the south;
high potential to occur in
the study area.
Roseaceae Rose Family
Horkelia cuneata ssp.
puberula
Mesa horkelia 1B.1 Prefers chaparral,
woodland, and coastal
scrub habitats.
Moderate potential to
occur in the study area.
Notes:
1. Federally listed as endangered
CNPS Listing Status:
List 1B - Plants Rare, Threatened, or Endangered in California and elsewhere
List 2 - Plants Rare, Threatened, or Endangered in California, but more common elsewhere
List 3 - Plants about which we need more information – a review list
List 4 - Plants of limited distribution – a watch list
The CNPS recently added “threat ranks,” which parallel the ranks used by the California Natural Diversity Database (CNDDB). These ranks are added as a decimal code after the CRPR List (e.g., List 1B.1). The threat codes are as follows:
0.1 - Seriously endangered in California (over 80% of occurrences threatened/high degree and immediacy of threat)
0.2 - Fairly endangered in California (20–80% occurrences threatened)
0.3 - Not very endangered in California (<20% of occurrences threatened or no current threats known)
Source: California Native Plant Society, 2019.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-18
Special-Status Wildlife Species
The CNDDB listed 27 sensitive wildlife species in the Planning Area.
Table 5-2 provides a summary of the sensitive wildlife species with a low,
moderate, or high potential of occurring within the City based upon
their known geographic ranges, distributions, and preferred habitats. A
selection of these species within close proximity to the Planning Area are
mapped in Figure 5-3.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
INVERTEBRATES
Bombus crotchii Crotch
bumblebee
S1S2
G3G4
Recorded at scattered
locations in southern
California.
High potential to occur in
study area.
Helminthoglypta
tudiculata
Southern
California
shoulder-band
snail
S1S2 Recorded at scattered
locations in southern
California.
High potential to occur in
study area.
Helminthoglypta
traskii
Trask’s shoulder-
band snail
G1G2
S1
Recorded at scattered
locations in southern
California.
High potential to occur in
study area.
VERTEBRATES
Amphibians
Pelobatidae Spadefoot Toad
Family
Spea hammondii Western
spadefoot
SSC Open areas in lowland
grasslands, chaparral,
and oak woodlands,
areas of sandy or
gravelly soil in alluvial
fans, washes, and
floodplains.
High potential to occur in
the study area.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-19
RESOURCE CONSERVATION 5.0
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Salamandridae Newt Family
Taricha torosa Coast range
newt
SSC Moist woodlands.Not recorded in the
Puente/Chino Hills; low
potential to occur in the
study area.
Reptiles
Colubridae Colubrid Snake
Family
Lampropeltis zonata
pulchra
San Diego
mountain
kingsnake
SSC Moist woods,
woodlands, chaparral
and sage scrub.
Moderate potential to
occur in study area.
Salvador hexalepis
virgultea
Coast patch-
nosed snake
SSC Sage scrub, chaparral,
and oak/walnut
woodlands.
Moderate potential to
occur in study area.
Thamnophis
hammondii
Two-striped
garter snake
SSC Riparian and freshwater
marshes with perennial
water.
Moderate potential to
occur in the study area.
Arizona elegans
occidentalis
California glossy
snake
SSC Sage scrub, chaparral,
and oak/walnut
woodlands with loose
soil for burrowing.
Moderate potential to
occur in the study area.
Emydidae Turtle Family
Emmys marmorata Western pond
turtle
SSC Ponds, slow moving
streams.
Known to occur in
Brea Creek; moderate
potential to occur
in suitable habitat
elsewhere in the study
area.
Iguanidae Iguanid Lizard
Family
Phrynosoma blainvillii Coast horned
lizard
SSC Most valley and foothill
scrub, chaparral and
woodland natural
communities.
High potential in open
space in the study area.
Teiidae Whiptail Lizard
Family
Anniella stebbinsi Southern
California legless
lizard
SSC Several habitats but
especially in valley-
foothill woodlands,
chaparral, and scrub
habitats.
Moderate potential in
habitats in the study area.
Aspidoscelis tigris
stejnegeri
Coastal whiptail SSC Several habitats but
especially in valley-
foothill woodlands,
chaparral, and scrub
habitats.
High potential in habitats
in the study area.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-20
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Viperiidae Viper Snake
Family
Crotalus ruber Red diamond
rattlesnake
SSC Cactus and sage scrub
and chaparral.
High potential in suitable
habitats in the study area.
Birds
Accipitridae Hawks, Kites,
Harriers and
Eagle Family
Aquila chrysaetos Golden eagle SSC, SFP,
FP
Mountains, deserts, and
open country; prefer to
forage over grasslands,
deserts, savannahs
and early successional
stages of forest and
shrub habitats.
Recorded over the study
area; nesting in the Chino
Hills; High potential to
forage within the study
area.
Circus hudsonius Northern harrier SSC Freshwater marshes,
grasslands, and
agricultural fields.
Recorded in the Tres
Hermanos and Firestone
Scout Reservation areas.
Elanus leucurus White-tailed kite SFP Grasslands with
scattered trees,
near marshes, along
highways.
Recorded in the Tres
Hermanos and Firestone
Scout Reservation areas.
High potential in study
area.
Buteo regalis Ferruginous
hawk
SBSWG Winters in expansive
rangelands and
agricultural areas in the
region.
Recorded in the Chino
Basin; moderate potential
to occur in the study
area.
Alaudidae Lark Family
Eremophila alpestris Horned lark SBSWG Open ground.Moderate potential
to occur in the Tres
Hermanos and SOI areas.
Falconidae Falcon Family
Falco mexicanus Prairie falcon SBSWG Open country,
especially arid.
Moderate potential to
occur migrating through
the study area.
Stringidae True Owl Family
Athene cunicularia Burrowing owl SSC Dry grasslands and
agricultural, and scrub
areas.
Reported from the Tres
Hermanos Ranch High
potential to occur within
the study area.
Asio otus Long-eared owl SSC Riparian and live oak
woodlands.
High particularly in oak
and walnut woodlands.
Asio flammeus Short-eared owl SSC Winters in open areas.Low potential in
herbaceous stands.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-21
RESOURCE CONSERVATION 5.0
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Troglodytidae Wren Family
Campylorhynchus
brunneicapillus
Coastal cactus
wren
SSC Coastal sage scrub,
vegetation with thickets
of prickly pear or cholla
cactus.
Recorded at Sycamore
Canyon and Summit
Ridge Parks; High
potential wherever
cactus scrub occurs.
Turdidae Bluebird Family
Sialia currucoides Mountain
bluebird
SBSWG Winters in open country.Moderate potential
to occur in the Tres
Hermanos and SOI areas.
Tyrannidae Tyrant Flycatcher
Family
Empidonax traillii Willow flycatcher FE, SE Low elevational sites:
Riparian woodlands
that contain water and
low growing willow
thickets.
Low potential for nesting.
Icteriidae Yellow-breasted
chat Family
Icteria virens Yellow-breasted
chat
SSC Riparian woodlands
with a thick understory.
High potential along Brea
and Tonner Creeks.
Sturnella neglecta Western
meadowlark
SBSWG Grasslands, prairies,
pastures, and
abandoned fields.
Recorded in the study
area.
Icteridae Blackbird Family
Agelaius tricolor Tricolored
blackbird
SE Freshwater marshes
and riparian scrub.
Moderate potential to
forage in open areas
of Tres Hermanos and
Tonner Canyon.
Laniidae Shrike Family
Lanius ludovicianus Loggerhead
shrike
SSC Open habitats with
scattered shrubs, trees,
posts, fences, utility
lines, or other perches.
High potential to occur
in Tres Hermanos and
Tonner Canyon open
areas.
Passerellidae Sparrow Family
Ammodramus
savannarum
Grasshopper
sparrow
SSC Expansive grasslands Recorded in the study
area; moderate potential
to occur in Tres Hermanos
and Tonner Canyon.
Amphispiza belli belli Bell’s sage
sparrow
SSC Dense, dry chamise
chaparral and coastal
slopes of coastal sage
scrub.
High potential in study
area where habitat
occurs.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-22
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Pooecetes gramineus Vesper sparrow SBSWG Open grassy areas.High potential to occur
in Tres Hermanos and
Tonner Canyon open
areas.
Parulidae Wood Warbler
Family
Setophaga petechia Yellow warbler SSC Sparse to dense
woodland and forest
habitats with or without
heavy brush understory.
High Potential in oak,
rirarian and walnut
woodlands.
Polioptilidae Gnatcatchers
Polioptila californica California
gnatcatcher
FT, SSC Coastal sage scrub
vegetation; generally
avoids steep slopes and
dense vegetation for
nesting.
Several recent recorded
occurrences in the study
area at Summit Ridge,
and Pantera parks, Steep
Canyon and hills south
of Diamond Ranch High
School; high potential in
sage scrub habitats.
Vireonidae Vireo Family
Vireo bellii pusillus least Bell’s vireo FE, SE Perennial and
intermittent streams
with low, dense riparian
scrub and riparian
woodland habitats;
nests primarily in
willows and forages
in the riparian and
occasionally in
adjoining upland
habitats. Associated
with willow, cot
Reported from Tonner
Canyon; Moderate
potential to occur along
Brea Creek
Cuculidae Cuckoo Family
Geococcys
californianus
greater
roadrunner
SBSWG Open country with
scattered brush.
Recorded in the study
area.
Mammals
Heteromyidae Kangaroo Rat,
Pocket Mice, and
Kangaroo Mice
Family
Chaetodipus fallax NW San Diego
pocket mouse
SSC Sandy herbaceous
areas, usually in
association with rocks
or coarse gravel,
sagebrush, scrub,
annual grassland,
chaparral and desert
scrubs.
High potential in study
area particularly in
cactus and sage scrub
occurs.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-23
RESOURCE CONSERVATION 5.0
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Molossidae Free-tailed Bats
Eumops perotis
californicus
Western mastiff
bat
SSC In arid and semi-arid
lowlands; roosts in cliffs
and rock crevices.
Low potential for roosting
sites but may forage in
the study area.
Vespertilionidae Evening Bat
Family
Lasiurus blossevillii Western red bat Roosts in cliffs and in
buildings.
Moderate potential in
study area; roosts in
exfoliating bark on many
tree species including
ornamental trees.
Lasiurus xanthinus Western yellow
bat
SSC Roosts primarily in
palms under dead
fronds.
Moderate potential to
roost in the study area.
Antrozous pallidus Pallid bat SSC Roosts in cliffs, crevices,
mine tunnels, caves,
house attics and other
man-made structures.
High potential in study
area; roosts in exfoliating
bark on oak trees.
Leporidae Rabbit and Hare
Family
Lepus californicus
bennetti
San Diego black-
tailed jackrabbit
SSC Open brushlands and
scrub habitats.
Moderate potential to
occur throughout the
study area.
Muridae Mice, Rats, and
Vole Family
Neotoma lepida
intermedia
San Diego desert
woodrat
SSC Chaparral, coastal
sage scrub, and oak
woodland.
High potential to occur
where suitable habitat is
found.
Procyonidae Raccoon Family
Bassariscus astutus Ringtail cat SFP Commonly found in
rocky habitats, where
it nests in the hollows
of trees or abandoned
wooden structures.
Seldom observed; low
potential to occur in the
study area.
Mustelidae Weasel Family
Taxidea taxus American
badger
SSC Open grasslands with
available prey.
High potential to occur in
the study area.
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-24
Scientific Name Common Name Agency Listing Status
Preferred Habitat Records
Notes: Agency Listing Status:
FE Federally listed as Endangered
FT Federally listed as Threatened
FP Federally protected
SE State-listed as Endangered
SFP State Fully Protected
SSC California Species of Special Concern
NatureServe Ranking:
S1 = Critically Imperiled—Critically imperiled in the state because of extreme rarity (often 5 or fewer populations) or because of factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.
S2 = Imperiled—Imperiled in the state because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation from the state.
S3 = Vulnerable—Vulnerable in the state due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors making it vulnerable to extirpation from the state.
S4 = Apparently Secure—Uncommon but not rare in the state; some cause for long-term concern due to declines or other factors.
S5 = Secure—Common, widespread, and abundant in the state.
G1 = Critically Imperiled—At very high risk of extinction due to extreme rarity (often 5 or fewer populations), very steep declines, or other factors.
G2 = Imperiled—At high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors.
G3 = Vulnerable—At moderate risk of extinction due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors.
G4 = Apparently Secure—Uncommon but not rare; some cause for long-term concern due to declines or other factors.
G5 = Secure—Common; widespread and abundant.
Source: California Department of Fish and Wildlife Natural Diversity Database, 2018
Table 5-2: Special Status Plant Species Occuring or Potentially Ocurring
within the Planning Area
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-25
RESOURCE CONSERVATION 5.0
There may be occurrences of
additional species within this
area that have not yet been
surveyed and/or mapped. Lack of
information in the CNDDB about a
species or an area does not imply
that the species does not occur
or that there is a lack of diversity
in that area. The species shown
in Figures 5-3 and 5-4 have the
potential to occur outside of the
areas where they are depicted.
Given the occurrence of these
special-status species within
Diamond Bar and its SOI and the
potential for others to exist within
and surrounding the City, it will be
important for the City to ensure
the maintenance and protection
of the habitats that support them.
Strategies may include ensuring
that new development avoids or
mitigates any impacts that would
degrade the healthy function of
nearby habitat areas and exploring
programs such as conservation
or mitigation banking that can
preserve, enhance, restore, or
create habitat conservation areas
that may be threatened by new
development.
Sensitive plants include those listed, or
candidates for listing, by the U.S. Fish and
Wildlife Service (USFWS) and California
Department of Fish and Wildlife (CDFW),
and species considered sensitive by the
California Native Plant Society (CNPS),
particularly Lists 1A, 1B, and 2.
Sensitive wildlife species include
those species listed as endangered
or threatened under the Federal
Endangered Species Act (FESA) or
California’s Endangered Species Act
(CESA), candidates for listing by USFW or
CDFW, State Species of Special Concern
(SSC) by the CDFW, fully protected by
CDFW, or on the CDFW watch list.
A conservation or mitigation bank
is privately or publicly owned land
managed for its natural resource
values. In exchange for permanently
protecting, managing, and monitoring
the land, the bank sponsor is allowed
to sell or transfer habitat credits to
developers and permitees who must
satisfy legal requirements to compensate
for the environmental impacts of their
developmental project.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-26
WILDLIFE MOVEMENT
Wildlife movement corridors are
generally defined as connections
between blocks of habitat that
allow for physical movement
and genetic exchange between
otherwise isolated animal
populations. Movement corridors
may be local, such as between
foraging and nesting or denning
areas, or they may be regional in
nature, allowing animals to access
alternative territories as fluctuating
dispersal pressures dictate. In the
absence of wildlife corridors, various
studies have concluded that some
wildlife species, especially the larger
and more mobile mammals, will not
likely persist over time in fragmented
or isolated habitat areas because
such conditions preclude the
infusion of new individuals and
genetic information into isolated
populations.
Tonner Canyon, to the southeast of
the City, is an important part of a
regional wildlife movement corridor,
known as the Puente-Chino Hills
Wildlife Corridor, that provides a
linkage between the Cleveland
National Forest in the Santa Ana
Mountains through the Chino Hills
and the Puente Hills. Its importance
is due not only to its being largely
undeveloped, but also because it
funnels wildlife movement to the
only natural undercrossing of SR-57.
The Puente-Chino Hills Wildlife
Corridor has been the focus of
the Wildlife Corridor Conservation
Authority, a public and private
coalition, and the Puente Hills
Landfill Native Habitat Preservation
Authority, which obtain funds to
purchase land for the corridor.
Critical Habitat
Critical habitat is defined by the
Endangered Species Act as a
specific geographic area that
contains features essential for the
conservation of a threatened or
endangered species and that may
require special management and
protection. USFWS-designated
critical habitat does not occur
within the City.
Sensitive Natural Communities
Three plant communities considered
sensitive by the California
Department of Fish and Wildlife
(CDFW) due to their scarcity and/
or because they support special
status plant and wildlife species
have been identified in the
Planning Area. These communities
are considered highly imperiled
communities by the CDFW,
indicating that they are declining
in acreage throughout their
range due to land use changes.
These communities are described
previously and include Venturan
coastal sage scrub, southern
willow scrub, and California walnut
woodland.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-27
RESOURCE CONSERVATION 5.0
PUENTE HILLS SIGNIFICANT ECOLOGICAL AREA
Significant Ecological Areas (SEAs) are officially designated by Los Angeles
County as areas with irreplaceable biological resources. The SEA program
is intended to conserve genetic and physical diversity within the county
by designating biological resource areas that are capable of sustaining
themselves into the future. The intent of the SEA program is established in
the County’s General Plan, and the permitting, design standards, and review
process for development within SEAs are detailed in the SEA Ordinance
(Chapter 22.102 of the County Zoning Regulations). The SOI is designated
as SEA 15, Puente Hills. The Puente Hills SEA has documented evidence of
significant wildlife movement and is the County portion of a continuous
series of open spaces within the Puente and Chino hills. It functions as both
an important wildlife linkage and resident habitat area for regional wildlife
populations. A detailed description of the extents of this SEA as well as its
biological resources can be found in Appendix E of the 2035 Los Angeles
County General Plan.
Certain uses of the SEAs are compatible by definition with the long-term
sustainability of biological resources. Some examples of uses that do
not conflict with the goals of the SEA Program include regulated scientific
study; passive recreation, including wildlife observation and photography;
and limited picnicking, riding, hiking and overnight camping. Many other
uses may also be compatible with the SEA Program or may partially or
fully mitigate against potential impacts through careful site design and
stewardship, including low-density or low-intensity uses, essential public
uses, agricultural uses, and extractive uses. More complex or intensive types
of developments within SEAs are not precluded from development but may
require additional technical review to ensure that projects properly identify
existing resources and potential impacts.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-28
!(T
Intermediate
Mariposa-Lily
Many-Stemmed
Dudleya
Robinson's
Pepper-Grass
Intermediate
Mariposa-Lily
Intermediate
Mariposa-Lily
Intermediate
Mariposa-Lily
San Bernardino
Aster
Plummer's
Mariposa-Lily
Intermediate
Mariposa-Lily
Robinson's
Pepper-Grass
Many-Stemmed
Dudleya Mesa Horkelia
Walnut
Pomona
Industry
LOS ANGELES
COUNTY
ORANGE COUNTY
SAN BERNARDINO
COUNTY
Metrolink
Station
San
Dimas
Brea BREACANYONRDGOLDENSPRINGSDRCHINOHILLSPKWYG O LD EN SPRINGSDRGRANDAVE DIAMONDBARBLVDDIAMONDBARBLVDBREACANYONRDG O LD E N S P R I N G S D R
LYCOMING ST
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CASTLEROCKRD
PATHFINDERRD
W T E M P L E A V E
A M A R R D
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Robinson's Pepper-Grass
Intermediate Mariposa-Lily
Plummer's Mariposa-Lily
Many-Stemmed Dudleya
San Bernardino Aster
Mesa Horkelia
Major Highways
City of Diamond Bar
Sphere of Influence
County Boundary
0120.5
MILESSource: CNDDB, 2019; Dyett & Bhatia, 2019 RiversideMetrolinkLineDisclaimer: Information presented in this map is based on data
from CNDDB version April 2019. Areas of occurence on
this map represent areas in which known locations of the
species listed here have been found as of the date of this version.
There may be additional occurences of additional species within
this area which have not yet been surveyed and/or mapped. Lack
of information in the CNDDB about a species or an area can never
be used as proof that no special species occur in an area. CNDDB
can be contacted for more information about these occurences.
Figure 5-3: Special Status Plant Species City of Diamond Bar
GENERAL PLAN UPDATEFigure 5-3 Special Status Plants
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION 5-29
Red-Diamond
Rattlesnake
Southern California
legless lizard
California
glossy snake
Walnut
Pomona
Industry
LOS ANGELES
COUNTY
ORANGE COUNTY
SAN BERNARDINO
COUNTY
Metrolink
Station
San
Dimas
Brea BREACANYONRDGOLDENSPRINGSDRCHINOHILLSPKWYG O LD EN SPRINGSDRGRANDAVE DIAMONDBARBLVDDIAM ONDBARBLVDBREACANYONRDG O L D E N S P R I N G S D R
LYCOMING ST
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MO
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CASTLEROCKRD
PATHFINDERRD
W T E M P L E A V EGRANDAVE
A M A R R D
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V IA V E R D E
GRAND A VEPEYTONDRSGAREYAVEPHILADELPHIA ST
60
71
57
10
57
57
1057
60
Golden Eagle
Big
Free-Tailed
BatWestern
Yellow Bat
Yellow-Breasted
Chat
Long-Eared
Owl
Pocketed
Free-Tailed
Bat
Cooper's
Hawk
Coastal
Whiptail
Western
Pond
Turtle
Coastal
California
Gnatcatcher
Red-Diamond
Rattlesnake
Merlin
Western
Mastiff Bat
Coastal
California
Gnatcatcher
Yellow
Warbler
Least
Bell's
Vireo
Tricolored
Blackbird
Coastal
California
Gnatcatcher
Yellow
Warbler
Coastal
California
Gnatcatcher
Coast
Horned
Lizard
Grasshopper
Sparrow
Least
Bell's
Vireo
Least
Bell's
Vireo
Least Bell's
Vireo
California
Horned Lark
Southern
California
Rufous-Crowned
Sparrow
Least Bell's
Vireo
Yellow
Warbler
Southern California
Rufous-Crowned
Sparrow
Least Bell's
Vireo
Western Pond
Turtle
Coast
Horned
Lizard
Coastal Cactus
Wren
Coastal
California
Gnatcatcher
Yellow
Warber
Yellow-Breasted
Chat
Western
Pond Turtle
0 1 20.5
MILESRiversideMetrolinkLineDisclaimer: Information presented in this map is based
on data from CNDDB version October 2019. Areas
of occurence on this map represent areas in which
known locations of the species listed here have been
found as of the date of this version. There may be
additional occurences of additional species within this
area which have not yet been surveyed and/or mapped.
Lack of information in the CNDDB about a species or
an area can never be used as proof that no special
species occur in an area. CNDDB can be contacted
for more information about these occurences.
Source: Hamilton Biological, 2019; CNDDB, 2019; Dyett & Bhatia, 2019
Endangered/Threatened Species
California black rail
Coastal California Gnatcatcher
Least Bell's Vireo
Other Species
White-tailed kite
California glossy snake
Arroyo chub
American badger
Southern California legless lizard
Southern California Rufous-Crowned Sparrow
Western Yellow Bat
Golden Eagle
Long-Eared Owl
Yellow Warbler
Northern Harrier
Western Mastiff Bat
Yellow-Breasted Chat
California Horned Lark
Cooper's Hawk
Big Free-Tailed Bat
Coast Horned Lizard
Coastal Cactus Wren
Coastal Whiptail
Grasshopper Sparrow
Merlin
Pocketed Free-Tailed Bat
Red-Diamond Rattlesnake
Tricolored Blackbird
Western Pond Turtle
City of Diamond Bar
Figure 5-4: Special Status Animals C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATEFigure 5-4 Special Status Animals
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-30
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Pomona
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LOS ANGELES
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Choke Points
Natural Communities
Developed
City of Diamond Bar
Sphere of Influence
0 0.75 1.50.375
MILES
Source: City of Diamond Bar 2019;
ESA PCR, 2016; Dyett & Bhatia, 2019 RiversideMetrolinkLineFigure 5-5: Movement Choke Points
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LOS ANGELES
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Choke Points
Natural Communities
Developed
City of Diamond Bar
Sphere of Influence
0 0.75 1.50.375
MILES
Source: City of Diamond Bar 2019;
ESA PCR, 2016; Dyett & Bhatia, 2019 RiversideMetrolinkLineFigure 5-5: Movement Choke PointsFigure 5-5: Movement Choke Points
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
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5-31
GOALS & POLICIES
BIOLOGICAL RESOURCES
GOALS
RC-G-4 Maintain, protect, and preserve biologically
significant areas, including Significant
Ecological Area (SEA) 15, riparian areas,
oak and walnut woodlands, and other
areas of natural significance, providing
only such recreational and cultural
opportunities as can be designed in
a way that sustains, repairs or restores
ecosystems rather than detracts from them.
RC-G-5 Protect rare, threatened, endangered, and
other special-status plant and
animal communities.
RC-G-6 Utilize native and drought-tolerant
vegetation in landscaping, site stabilization
and restoration where practical to
prevent the spread of invasive plant
species into natural open spaces.
POLICIES
RC-P-9 Require, as part of the environmental review
process prior to approval of discretionary
development projects involving parcels
within, adjacent to, or surrounding a
significant biological resource area, a
biotic resources evaluation of the site by a
qualified biologist. Focused plant surveys
shall be conducted at the appropriate time
of year, and local reference populations
checked to ensure detectability of the target
species. Wildlife shall also be evaluated by
a qualified biologist through appropriate
survey or trapping techniques necessary
to determine presence. Such evaluation
shall analyze the existing and potential
natural resources of a given site as well as
the potential for significant adverse impacts
on biological resources. The report shall
identify measures to avoid, minimize, or
mitigate any impacts to species that have
been observed or have the potential of
being present on the site. In approving any
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-32
permit based on the evaluation, the City shall
require implementation of mitigation measures
supported by the evaluation, or work with the
applicant to modify the project if mitigation
is determined not to be adequate to reduce
the impacts to a non-significant level.
RC-P-10 Require, to the greatest extent feasible, new
development to preserve mature native
trees including oak and walnut, and trees of
significant cultural or historical value such as
sycamore and arroyo willow, etc., as set forth
under the Diamond Bar Tree Preservation
and Protection Ordinance. Review the
ordinance periodically and update it as
necessary to reflect current best practices.
RC-P-11 Require that all development, including roads
and trails, proposed adjacent to riparian and
other biologically sensitive habitats avoid, to the
greatest extent feasible, significant impacts that
would undermine the healthy natural functioning
of those areas. Require that new development
proposed in such locations be designed to:
a. Minimize to the greatest extent possible or
eliminate impacts on environmentally
sensitive areas;
b. Protect the visual seclusion of forage areas
from road intrusion by providing vegetative
buffering;
c. Protect wildlife movement linkages to water,
food, shelter, and nesting sites;
d. Allow wildlife and migration access by use of
tunnels or other practical means.
e. Provide vegetation that can be used by
wildlife for cover along roadsides;
f. Avoid intrusion of night lighting into identified
areas through properly
designed lighting systems;
g. Avoid impacts to wetlands, natural springs
and seeps and maintain access for wildlife
or when natural water areas are
removed or blocked provide a locally
suitable and equal replacement; and
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
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GOALS & POLICIES
h. To the greatest extent possible, prevent
street water runoff from flowing into
waterways.
RC-P-12 Support and cooperate with the efforts of other
local, State, and federal agencies, groups, and
private entities—including Los Angeles County,
neighboring jurisdictions, and conservation
groups—to preserve environmentally sensitive
hillsides, canyon areas, wildlife corridors and
riparian areas within Diamond Bar’s SOI,
including the Puente - Chino Hills Wildlife
Corridor, Tres Hermanos Ranch, Tonner Canyon,
and SEA 15 to provide regional connectivity,
and to sustain the ecological function of
natural habitats and biological resources.
a. Discourage development in areas with
identified significant biological
resources, such as SEAs.
b. Discourage development in riparian
habitats, streambeds, wetlands, coastal sage
scrub, cactus scrub, and native woodlands
in order to maintain and support their
preservation in a natural state, unaltered
by grading, fill, or diversion activities.
c. Preserve and restore oak woodlands and
other native woodlands that are
conserved in perpetuity with a goal of
no net loss of existing woodlands.
RC-P-13 Utilize native and drought-tolerant plants in
landscaping for public buildings and parks
and encourage the use of native and drought-
tolerant species on private property. Develop
a list of recommended native, low-water-
use, and drought-tolerant plant species, as
well as a list of invasive species to avoid.
RC-P-14 Support and cooperate with the efforts of local
school districts, environmental groups
and volunteers to offer environmental
education programs.
RC-P-15 Support efforts to establish mitigation bank
programs to restore habitat within Open
Space-designated and deed-restricted lands.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-34
5.5 WATER RESOURCES
HYDROLOGY
Diamond Bar is almost entirely
encompassed by the San Gabriel
River Basin, which spans 713 square
miles across Los Angeles and
Orange Counties. As shown in
Figure 5-5, the Planning Area drains
into four sub-basins of the San
Gabriel River Basin. The northern
half of the City primarily drains
into San Jose Creek, partially via
Diamond Bar Creek. Most of the
southern half of the City, as well as
the SOI, drains into Brea Canyon
Creek. Small areas in the northeast
of the City are within the Santa Ana
River Basin, draining locally into
Chino Creek.
The hydrological system is a critical
component of drainage and flood
management in the Planning Area,
as well as groundwater recharge
and potable water supply (see
Chapter 7, Public Safety for more
information on flood hazards and
Chapter 6, Public Facilities and
Services for more information
on water supply and stormwater
management). The Planning Area’s
hydrology can be affected by
development in the watershed that
increases the area of impervious
surfaces and reduces vegetative
coverage. This type of development
can reduce the amount of area
that can be used for groundwater
recharge and increase the volume
and speed of stormwater runoff,
which can lead to increased flood
risk and erosion of streambeds.
Development can also alter the
direction that water flows in a
watershed, leading to changes in
the size and location of surface
water bodies. Other changes to
surface water can come from
sediment from construction
activities and erosion. All of these
considerations are therefore
important issues to address as part
of the planning process when siting
and designing development.
GROUNDWATER MANAGEMENT
In 2014, California passed the
Sustainable Groundwater
Management Act (SGMA), to
provide a framework for sustainable,
local groundwater management.
The SGMA requires Groundwater
Sustainability Plans to be adopted
for medium- or high-priority basins
by a groundwater sustainability
agency (GSA). A Groundwater
Sustainability Plan must contain
a description of the setting and
characteristics of the basin,
measurable objectives to meet the
sustainability goal within 20 years
of implementation, a planning and
implementation horizon, monitoring
information and protocols, and
consideration of applicable general
plans. Diamond Bar is within the
boundaries of the Main San Gabriel,
Puente and Spadra groundwater
basins. Both the Main San Gabriel
Basin and Puente Basins have been
adjudicated, meaning they are
exempt from the SGMA due to their
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-35
RESOURCE CONSERVATION 5.0
proof of sustainable management.
In order to comply with the SGMA,
the Spadra Basin has created a
GSA and as of 2019 is developing a
Groundwater Sustainability Plan.
While the WVWD currently
imports all potable water from
the Metropolitan Water District
of Southern California (MWD),
the Water District has projects
underway that will produce
groundwater from the San Gabriel
Basin, Central Basin, and Six Basins
to supplement potable water
supplies. It will thus be important
for Diamond Bar to continue to
partner with other local agencies
and jurisdictions, including the
WVWD and groundwater basin
management agencies, to manage
surface and groundwater resources
given the constrained water
resources of the region.
WATER QUALITY
Water quality in the surface and
groundwater systems can be
affected by point and non-point
sources of pollution. Point sources
are single identifiable sources of
pollution, such as a pipe or a drain,
and can be agencies, businesses, or
other parties discharging directly to
a water body. The National Pollutant
Discharge Elimination System
(NPDES) is a federal program that
regulates point sources of pollution.
The City of Diamond Bar stormwater
system is regulated by the NPDES
Municipal Separate Storm Sewer
System (MS4) permit for Los Angeles
County.
Non-point pollution comes
from many diffuse sources, and
generally results from runoff,
drainage, seepage, or hydrologic
modification. Activities common to
life in Diamond Bar such as driving
and lawn maintenance produce
non-point source pollutants
that can enter surface water
or groundwater through runoff.
Stormwater runoff during storm
events, and runoff from irrigation
and other urban uses of water carry
contaminants such as gasoline, oil,
pesticides, herbicides, and fertilizer
into the river or groundwater supply.
At high enough concentrations,
runoff from these non-point sources
could impair uses of surface waters,
damage wildlife habitats, and
contaminate groundwater sources.
By protecting and improving
the quality of its surface and
groundwater bodies, the City
can help reduce the amount
of energy spent treating water
before it is used, and ensure the
health of habitats and ecosystems.
Steps that the City can take
include addressing sources
of non-point source pollution
related to development and the
transportation system, educating
residents about water consumption
and stormwater pollution
prevention, and working with
other agencies and organizations
to protect natural groundwater
recharge areas from contamination.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-36
Figure 5-6 Watersheds and Surface Water
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WatershedThompson WashLemonCreekSanJoseCreekD iversionC h a nnelDiam on d B a r Creek
D iamo n d B a r C r e e kSouthSanJoseCre
Sources: Esri, USGS, NOAA
Highways
Ramps
Major Roads
Local Roads
Railroads
Surface Water
Watershed (HU8)
Watershed (HU10)
Subwatersheds (HU12)
Brea Creek-Coyote Creek
Carbon Creek
Lower San Jose Creek
Upper Chino Creek
Upper San Jose Creek
Lakes/Ponds
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Source: City of Diamond Bar 2019; Los Angeles County GIS Data,
2016; National Hydrography Dataset, 2016; Dyett & Bhatia, 2019RiversideMetrolinkLineFigure 5-6: Watersheds and Surface Water
ekCity of Diamond Bar
GENERAL PLAN UPDATE
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
5.0
5-37
GOALS & POLICIES
WATER RESOURCES
See Chapter 2: Land Use and Economic Development for
policies regarding water use and distribution.
GOALS
RC-G-7 Protect waterways—including creeks, riverines,
artesian springs, seeps, and wetlands—and
watersheds in Diamond Bar from pollution and
degradation as a result of urban activities.
RC-G-8 Protect natural groundwater recharge areas
and regional spreading grounds.
RC-G-9 Conserve natural open spaces, biological
resources, and vegetation to
promote groundwater recharge.
RC-G-10 Minimize the consumption and waste of
potable water through water conservation
and use of reclaimed water.
RC-G-11 Work with regional organizations and other
jurisdictions to manage groundwater
resources of the San Gabriel Valley Basin.
RC-G-12 Pursue methods to control, capture, and reuse
stormwater runoff for the purposes
of groundwater recharge and
local water recovery.
POLICIES
Water Conservation
RC-P-16 As opportunities arise, coordinate with local
water agencies to encourage and
expand the use of reclaimed water, stored
rainwater, or household gray water for
irrigation and other appropriate uses
and consider construction of dual water
systems, where feasible, for development
RC-P-17 Continually evaluate and upgrade the
efficiency of City irrigation systems,
prioritizing the use of reclaimed water.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-38
RC-P-18 Ensure new development reduces the waste of
potable water through the use of native
and drought-tolerant plants, efficient
landscape design and application, and
reclaimed water systems where available.
RC-P-19 Encourage the implementation of the latest
water conservation technologies
into new developments.
RC-P-20 Ensure developers provide information to
prospective buyers or tenants within
the City of Diamond Bar regarding
drought-tolerant planting concepts.
RC-P-21 Continue to partner with other local agencies
to manage surface and groundwater
resources through the implementation
of the Walnut Valley Urban Water
Management Plan and regional watershed
and groundwater planning efforts.
Water Quality
RC-P-22 Protect and, where feasible, enhance or
restore the City’s waterways and drainages,
preventing erosion along the banks,
removing litter and debris, and promoting
riparian vegetation and buffers.
RC-P-23 Ensure that post-development peak
stormwater runoff discharge rates
do not exceed the estimated pre-
development rate and that dry weather
runoff from new development not
exceed the pre-development baseline
flow rate to receiving water bodies.
Diamond Bar General Plan 2040 |RESOURCE CONSERVATION 5-39
RESOURCE CONSERVATION 5.0
5.6 AIR QUALITY
Air quality is often understood as
a regional issue, as the land use,
circulation, and growth decisions
made by individual communities
inevitably affect regional air quality.
The City of Diamond Bar is located
within the South Coast Air Basin
(Air Basin), which consists of the
entire Orange and Los Angeles
counties, and the western, non-
desert portions of San Bernardino
and Riverside Counties, in addition
to the San Gorgonio Pass area in
Riverside County. The South Coast
Air Quality Management District
(SCAQMD) is the air pollution control
agency for the Air Basin, and it
adopts air quality management
plans (AQMP) to achieve air quality
standards in the Air Basin. The
district includes Orange County,
most of Los Angeles County,
and the western portions of San
Bernardino and Riverside counties.
The Air Basin is one of only
two areas in the country with
extreme nonattainment levels
for the federal ozone standard,
as indicated in Table 5-3. As of
2012, mobile sources, including
cars, trucks, boats, and planes
contributed to approximately 88
percent of emissions in the Air
Basin. Additionally, the Air Basin
also experiences high levels
of fine particulate matter. The
extent and severity of pollutant
concentrations in the Air Basin is
a function of the area’s natural
physical characteristics (weather
and topography) and man-made
influences (development patterns
and lifestyle). Factors such as wind,
sunlight, temperature, humidity,
rainfall, and topography all affect
the accumulation and dispersion of
pollutants.
Based on the overall air quality
trends of the Air Basin, the largest
source of emissions impacting air
quality in Diamond Bar comes from
mobile sources, particularly given
the presence of the SR-57 and
SR-60 freeways in the community.
Ensuring air quality for individual
sites will mean assessing and
mitigating the potential impacts of
specific pollutant sources such as
the freeways. At the citywide and
regional levels, the most promising
actions to improve air quality would
be to not only mitigate emissions
from stationary sources, but to also
reduce vehicle miles traveled (VMT).
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-40
Table 5-3: South Coast Air Basin Attainment Status
(Los Angeles County)
Pollutant National Standards California Standards
O3 (1-hour standard)N/A1 Non-attainment – Extreme
O3 (8-hour standard)Non-attainment – Extreme Non-attainment
CO Attainment Attainment
NO2 Attainment Non-attainment
SO2 Attainment Attainment
PM10 Attainment Non-attainment
PM2.5 Non-attainment Non-attainment
Lead Non-attainment Non-attainment
Visibility Reducing Particles N/A Unclassified
Sulfates N/A Attainment
Hydrogen Sulfide N/A Unclassified
Vinyl Chloride N/A N/A2
Notes:
1. The NAAQS for 1-hour ozone was revoked on June 15, 2005, for all areas except Early Action Compact areas.
2. In 1990 the California Air Resources Board identified vinyl chloride as a toxic air contaminant and determined that it does not have an identifiable threshold. Therefore, the California Air Resources Board does not monitor or make status designations for this pollutant.
CRITERIA POLLUTANTS
Certain air pollutants have been designated as “criteria” air pollutants
because they are common and widely distributed, and are known to
have adverse human health effects and/or cause adverse impacts to
the environment either directly or through reactions with other pollutants.
Criteria air pollutants are indicators of ambient air quality and include:
ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide
(SO2), respirable or breathable particulate matter with an aerodynamic
diameter of 10 micrometers or less (PM10), fine particulate matter with
an aerodynamic diameter of 2.5 micrometers or less (PM2.5), and lead.
The criteria pollutants are regulated by the United States Environmental
Protection Agency (EPA) at the national level and by the California Air
Resources Board (CARB) at the State level, and are subject to respective
ambient air quality standards adopted by EPA and CARB.
Diamond Bar General Plan 2040 | RESOURCE CONSERVATION
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5-41
GOALS & POLICIES
AIR QUALITY
See Chapter 2: Land Use and Economic Development for
policies regarding land use and development patterns. See
Chapter 4: Circulation for policies regarding the reduction
of VMT and multi-modal transportation. See Chapter 8:
Community Health for policies regarding energy efficiency
and conservation.
GOALS
RC-G-13 Protect the City’s air quality and support efforts
to protect and improve regional air quality.
RC-G-14 Aim for a diverse and efficiently-operated local
and regional ground transportation system
that reduces VMT and generates the
minimum amount of pollutants feasible.
POLICIES
RC-P-24 Encourage new development to minimize
impacts on air quality through
the following measures:
a. Use of building materials and methods that
minimize air pollution.
b. Use of fuel-efficient heating equipment,
and other appliances, such as water
heaters, swimming pool heaters,
cooking equipment, refrigerators,
furnaces, boiler units, and low or zero-
emitting architectural coatings.
c. Use of clean air technology beyond what is
required by South Coast Air Quality
Management District (SCAQMD),
leveraging State and local funding sources.
RC-P-25 Conserve natural open spaces, biological
resources, and vegetation, recognizing
the role of these resources in the reduction
and mitigation of air pollution impacts, and
the promotion of CO2 sequestration.
RC-P-26 Ensure that new development projects are
designed and implemented to be
consistent with the South Coast Air
Quality Management Plan.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-42
RC-P-27 To the extent practicable, maintain a system
of air quality alerts (such as through
the City website, internet, e-mail to
City employees, and other tools)
based on SCAQMD forecasts.
RC-P-28 Cooperate with the ongoing efforts of the
U.S. Environmental Protection Agency
(EPA), SCAQMD, the Southern
California Association of Governments
(SCAG), and the State of California
Air Resources Board in improving air
quality in the regional air basin.
RC-P-29 Ensure that project applicants consult with
SCAQMD when siting new facilities with
dust, odors, or Toxic Air Contaminant (TAC)
emissions to avoid siting those facilities near
sensitive receptors and avoid siting sensitive
receptors near sources of air pollution.
Examples of facilities that may emit TACs
as identified by the SCAQMD include
dry cleaners, gas stations, auto
body shops, furniture repair shops,
warehouses, printing shops, landfills,
recycling and transfer stations, and
freeways and roadways. Refer to
SCAQMD guidance for the most current
list of facilities that may emit TACs.
RC-P-30 For new or modified land uses that have the
potential to emit dust, odors, or TACs that
would impact sensitive receptors, require
the business owners to obtain all necessary
SCAQMD clearances or permits prior to
business license or building permit issuance.
Sensitive receptors include residences,
schools, childcare centers, playgrounds,
parks and other recreational
facilities, nursing homes, hospitals,
and other medical care facilities.
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GOALS & POLICIES
RC-P-31 Require new residential developments and
other sensitive uses (e.g. schools, daycare
centers, playgrounds, and medical facilities)
within 500 feet of a freeway to prepare an
air quality study of the site that evaluates
potential impacts of air pollution on sensitive
receptors and associated health risks and
identifies measures to feasibly mitigate any
impacts to protect the health of residents.
The 500-foot buffer is based on a California
Air Resources Board recommendation
to avoiding the siting of sensitive uses
within 500 feet of a freeway. Because of
freeways are so integrated into Diamond
Bar’s landscape, it may be difficult to
prevent the siting of sensitive receptors
near the freeways in the future; thus,
mitigation measures would be needed for
such development. Mitigation measures
may include screens, ventilation/air
filtration systems, landscape buffering and
vegetation, building design measures that
locate operable windows, balconies and
building air intake away from the emission
source, and site design measures including
the incorporation of open spaces between
buildings to reduce air pollution build up.
RC-P-32 Promote and support available SCAQMD
incentives and funding mechanisms
that encourage retrofits to reduce air
quality impacts for existing sensitive
uses within 500 feet of a freeway.
RC-P-33 Require construction and grading plans to
include State and AQMD-mandated
measures to the maximum extent possible
fugitive dust and pollutants generated by
construction activities and those related
to vehicle and equipment cleaning,
fueling and maintenance as well as
mono-nitrogen oxides (NOx) emissions
from vehicle and equipment operations.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-44
RC-P-34 Facilitate communication among residents,
businesses and SCAQMD to quickly resolve
air pollution nuisance complaints.
RC-P-35 Promote transit-oriented, walkable, compact
development patterns, the provision
of non-polluting transportation
alternatives, and transportation
demand management measures to
reduce total vehicle miles traveled.
RC-P-36 Promote expansion of all forms of mass transit
to employment, entertainment, and other
major destinations in Los Angeles, Riverside,
Orange, and San Bernardino counties.
Support public transit providers in efforts to
increase funding for transit improvements
to supplement other means of travel.
RC-P-37 Seek grants and other external funding
opportunities to convert the City fleet
to zero emissions vehicles over time and
in a manner that is fiscally neutral in
comparison to conventional fuel vehicles.
RC-P-38 Design traffic plans, including suggested
truck routes, to minimize diesel truck
idling and the exposure of residential
neighborhoods and sensitive
receptors to diesel truck traffic.
RC-P-39 Reduce paved road dust emissions through
targeted street sweeping of roads subject
to high traffic levels and silt loadings.
RC-P-40 Continue to advocate at all levels of
government for improvements to the
confluence of the SR-57 and SR-60
freeways, including the construction of
the missing interchanges between the
two freeways, to reduce congestion
and delays on the freeways, as well as
affected surface streets and on/offramps.
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RESOURCE CONSERVATION 5.0
5.6 CULTURAL RESOURCES
HISTORICAL SETTING
The Gabrielino
Diamond Bar and the surrounding
area is located within Gabrielino
(Gabrieleño, Tongva, or Kizh)
territory. The Gabrielino were
among the wealthiest, most
populous, and most powerful of
the aboriginal ethnic nationalities
in Southern California. Named
after the San Gabriel Mission, the
Gabrielino occupied sections of
Los Angeles, Orange, and San
Bernardino counties, and the islands
of San Nicolas, Santa Catalina,
and San Clemente. The Gabrielino
subsisted on a variety of resources
in several ecological zones. Lithic
tools such as arrow points and
modified flakes were used to hunt
and process animals. A variety of
ground stone grinding implements,
such as the mortar, pestle, mano,
and metate, were used to prepare
food.
The settlement patterns of the
Gabrielino, and other nearby
groups such as the Juaneño and
Luiseño, were similar and they
often interacted through marriage,
trade, and warfare. The seasonal
availability of water and plant
and animal resources dictated
seasonal migration rounds with
more permanent villages and base
camps being occupied primarily
during winter and spring months.
In the summer months, the village
populations divided into smaller
units that occupied seasonal food
procurement areas. The more
permanent settlements tended
to be near major waterways and
food sources and various secular
and sacred activities, such as food
production and storage and tool
manufacturing, were conducted at
these areas.
European contact with the
Gabrielino that inhabited the City
and surrounding region began in
1542 when Spanish explorer, Juan
Rodriguez Cabrillo, arrived by
sea during his navigation of the
California coast. More explorers
followed, including Sebastian
Vizcaino in 1602, and Gaspar de
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-46
Portola in 1769. In 1771, Mission San
Gabriel was established and it
slowly integrated Gabrielinos from
the surrounding region. By 1833,
the California missions had been
secularized and most Gabrielinos
became laborers for the gentry
class.
The City of Diamond Bar
In 1840, the governor Juan Alvarado
deeded 4,340 acres, including parts
of Diamond Bar, to Jose de la Luz
Linares. Linares established Rancho
Los Nogales, or “Ranch of the
Walnut Tree,” with this Mexican land
grant. After he died, Linares’ widow
sold a choice portion of the ranch
to Ricardo Vejar.
Starting in 1864, the land that
encompassed the original Rancho
Los Nogales changed ownership
several times. One such owner was
Louis Phillips, a young livestock
owner who subdivided portions
of the ranch for sale. Frederick E.
Lewis II purchased 7,800 acres of
the original ranch in 1918 and soon
thereafter formed the Diamond
Bar Ranch and registered the
“diamond over a bar” branding
iron with the California Department
of Agriculture. This would later
become the symbol for which the
City of Diamond Bar was named.
In 1943, Lewis sold the Ranch to the
Bartholomae family, who continued
to maintain it as a successful cattle
ranch for the next 13 years. William
A. Bartholomae was president of
the family oil company and in 1956
sought to make a more lucrative use
of the land. At that time the Ranch
looked much as it did in 1840,
with grassy rolling hills supporting
large herds of cattle, as well as
abundant walnut tree orchards
and scattered oak trees. The
Christiana Oil Corporation and the
Capital Oil Company, a subsidiary
of the Transamerica Corporation,
purchased 8,000 acres of Brea
Canyon for $10,000,000, which
encompassed the Ranch and the
Ranch Headquarters Compound.
Their plan was to develop a master-
planned community that would
eventually become home to more
than 50,000 people.
A master plan was adopted in 1958
and work began immediately on
utilities and infrastructure. The plan
included a central business district,
two shopping districts, and parks
including an 18-hole golf course.
Education was also considered a
very important aspect of the plan.
The first model homes were built
in 1960 in the north end of the City
and the development continues
to exist to this day. The City of
Diamond Bar incorporated in 1989,
becoming Los Angeles County’s
86th city.
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RESOURCE CONSERVATION 5.0
CULTURAL RESOURCES
Cultural resources include sites,
buildings, structures, or objects that
may have archaeological, historical,
cultural, or scientific significance.
Cultural resources include historic
resources, archaeological resources,
tribal cultural resources, and
paleontological resources. All of
these cultural resources provide a
link to the people and the cultures
of the past and can enrich Diamond
Bar’s sense of heritage and identity.
Historic Resources
A historic resource is a building,
structure, object, prehistoric or
historic archaeological site, or
district possessing physical evidence
of human activities over 45 years
old. Historic resources are often
designated and listed on the
national, State, or a local register,
making them eligible for certain
protections or other benefits. The
National Register of Historic Places
(NRHP) is the nation’s official list
of historic places. The register is
overseen by the National Park
Service and requires that a resource
eligible for listing on the register
meet one of several criteria at
the national, State, or local level,
and also retain sufficient physical
integrity of those features necessary
to convey historic significance.
The California Office of Historic
Preservation (OHP) offers four
different registration programs,
including the California Historical
Landmarks, California Points of
Historical Interest, California Register
of Historical Resources (CRHR),
and the NRHP. Each registration
program is unique in the benefits
offered and procedures required.
If a resource meets the criteria for
registration, it may be nominated
by any individual, group, or local
government to any program at
any time. Resources do not need
to be locally designated before
being nominated to a State
program nor do they need to
be registered at the State level
before being nominated to the
National Register. The California
Register includes buildings, sites,
structures, objects, and districts
significant in the architectural,
engineering, scientific, economic,
agricultural, educational, social,
political, military, or cultural annals
of California. Resources listed in the
National Register are automatically
listed in the CRHR.
As of 2019, there are no registered
historic resources in the City of
Diamond Bar. Two built environment
resources have previously been
identified in the City, including a
small segment of the Union/Southern
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-48
Pacific Railroad and a ground water
tank/reservoir. The railroad segment
was originally recommended eligible
for the NRHP in 1999, but in 2009
was recommended ineligible at
the local, State, and national levels
due to loss of integrity. The water
tank/reservoir has been found to be
ineligible for the NRHP but has not
been evaluated at the State or local
levels. These resources are described
in Table 5-4.
Archaeological Resources
The National Parks Service defines
archaeological resources as any
material remains of human life
or activities that are at least 100
years of age and are capable of
providing scientific or humanistic
understandings of past human
behavior, cultural adaptation, and
related topics. As of 2019, seven
archaeological resources have been
recorded within City limits, including
five prehistoric archaeological
sites, one prehistoric isolate, and
one historic archaeological site.
An additional four resources were
found within a half-mile radius of
the City, including a prehistoric
archaeological site, two historic
isolates, and one prehistoric isolate.
Archaeological resources are
described in Table 5-4.
Tribal Cultural Resources
A tribal cultural resource is a site,
feature, place, cultural landscape,
sacred place, or object with cultural
value to a tribe that is included
or determined to be eligible for
inclusion in the California Register
of Historic Resources, included in a
local register of historical resources,
or otherwise determined to be
significant by the lead agency of
an environmental review process.
A search of the Native American
Heritage Commission (NAHC)
Sacred Lands File was positive for
the Planning Area. Additionally, the
long heritage of Native American
tribes in the region suggests that
the presence of tribal cultural
resources is a possibility that future
development will need to consider.
The identification of tribal cultural
resources can be supported by the
NAHC’s records but can only be fully
determined through consultation
with local Native American
tribes. Thus, maintaining good
communication with local tribes will
be critical to ensuring that resources
are respectfully preserved.
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Table 5-4: Previously Recorded Cultural Resources
Permanent No. (P19-) or Trinomial (CA-LAN-)
Description Date Recorded Eligibility for NRHP
City of Diamond Bar
19-189748 Built-environment resource consisting of a
ground water tank/reservoir
2010 Not eligible
19-186112 Built-environment resource consists of a
segment of the Union/Southern Pacific
Railroad.
1999 N/A
19-002805 Prehistoric archaeological site consists
of milling tools, discoidals, stone balls,
choppers, hammerstones, and cores.
2000 N/A
CA-LAN-1704 Prehistoric archaeological site consists
of surface scatter containing a chopper,
mano fragment, metate fragment and a
possible hammerstone.
1980 N/A
CA-LAN-852 Prehistoric archaeological site consisting
of two cores and one flake
1976 N/A
CA-LAN-853 Prehistoric archaeological site consisting
of chert cores and chert flakes
1976 N/A
19-101010 Prehistoric isolate consisting of a mano 2013 Not eligible
CA-LAN-3771 Historic archaeological site/ landscape
component consisting of more than 15
eucalyptus trees and a concrete debris
concentration associated with the historic
Diamond Bar Ranch Headquarters
2008 Not eligible
CA-LAN-854 Prehistoric archaeological site consisting
of a small lithic scatter
1976 N/A
N-CAN-33 Sacred Kizh oak woodland area 2017 Unevaluated
Within a Half-Mile of the City
CA-LAN-1414 Prehistoric archaeological site consisting
of several artifacts (flake, granitic facial
mano and granitic pestle fragment)
found in the escarpment of an
embankment
1988 N/A
19-100794 Historic isolate consisting of five pieces of
white earthenware flatware.
2010 Not eligible
19-100795 Historic isolate consisting of seven pieces
of white earthenware flatware.
2010 Not eligible
19-101223 Prehistoric isolate which consists of a
schist, basin metate fragment
2000 Not eligible
Source: SCCIC, 2016; NAHC SLF, 2019.
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-50
Paleontological Resources
Paleontological resources are the
fossil remains or traces of past life
forms, including both vertebrate
and invertebrate species, as well
as plants. The City of Diamond Bar
is underlain by marine-derived
sediments that are thousands of
feet thick as part of the fossiliferous
Puente Formation. Low lying terrain
areas (such as Brea Canyon and
San Jose Creek) consist of younger
Quaternary Alluvium derived from
the drainages, which are not known
to contain significant vertebrate
fossils in the uppermost layers.
However, at shallow depths there
are older sedimentary deposits
that have the possibility of yielding
significant vertebrate fossils.
Elevated portions of the Puente Hills
within the City also have exposures
of the marine late Miocene-aged
Puente/Monterey Formation with
potential for fossil deposits.
Paleontological records searches
have indicated that one vertebrate
fossil locality exists within the
boundaries of the City and that
several other localities from the
same sedimentary deposits occur
nearby. While shallow excavations
into younger Quaternary Alluvium
deposits within the City are not
likely to yield paleontological
resources, deeper excavations
within the City (that extend down
into older Quaternary deposits
or into the Puente Formation)
have the potential to encounter
paleontological resources.
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GOALS & POLICIES
CULTURAL AND HISTORIC RESOURCES
GOALS
RC-G-15 Protect and enhance Diamond Bar’s historic,
cultural and archaeological resources for the
educational, aesthetic, and environmental
contribution that they make to Diamond
Bar’s identity and quality of life.
POLICIES
Historical Resources
RC-P-41 Support property owners in seeking registration
of eligible historic structures and sites in
registration programs such as California’s
Historical landmarks, California Points
of Historical Interest, California Register
of Historical Resources, and the
National Register of Historic Places.
Archaeological Resources
RC-P-42 Establish a procedure for the management of
archaeological materials found on-site during a
development, including the following provisions:
a. If significant resources are known or
suspected to be present on a site, require
that a qualified archaeologist conduct
monitoring of building demolition and/
or construction grading activities.
b. If materials are found on-site during
construction activities, require that work
be halted until a qualified archaeologist
evaluates the find and makes a
recommendation for the preservation
in place or recovery of the resource.
RC-P-43 Seek to preserve discovered archaeological
resources in place to maintain the
relationship between the artifacts and their
archaeological context, where feasible.
RC-P-44 Preservation can be achieved through
measures such as planning construction to
avoid archaeological sites, incorporating
RESOURCE CONSERVATION | Diamond Bar General Plan 20405-52
sites within open space areas, capping
the site prior to construction, and
permanently protecting the site
using a conservation easement.
Tribal Cultural Resources
RC-P-45 Establish development processes to avoid the
disturbance of tribal cultural resources.
Where possible, seek to preserve resources in
place, exploring opportunities of permanent
protection of the resources where feasible.
RC-P-46 Conduct project-specific Native American
consultation early in the development
review process to ensure adequate data
recovery and mitigation for adverse impacts
to significant Native American sites. Ensure
that City staff and local developers are
aware of their responsibilities to facilitate
Native American consultation under
Senate Bill 18 and Assembly Bill 52.
Paleontological Resources
RC-P-47 Establish a procedure for the management of
paleontological materials found
on-site during a development,
including the following provisions:
a. If materials are found on-site during
grading, require that work be halted until
a qualified professional evaluates the find
to determine if it represents a significant
paleontological resource, and makes a
recommendation for the preservation
in place or recovery of the resource.
b. If the resource is determined to be
significant, the paleontologist shall
supervise removal of the material
and determine the most appropriate
archival storage of the material.
c. Appropriate materials shall be prepared,
catalogued, and archived at the
applicant’s expense and shall be retained
within Los Angeles County if feasible.
The City relies on a
comprehensive network of
public facilities and services to
ensure a high quality of life for
the members of its community.
These include parks and
recreation facilities; community
facilities such as schools and
libraries; utilities including
water, wastewater, and
stormwater; and services such
as solid waste management.
Each type of service or facility
has its own unique set of
opportunities and constraints
and will require different
strategies to adapt to future
growth and change.
PUBLIC
FACILITIES &
SERVICES 6.0
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-2
6.1 INTRODUCTION
The purpose of the Public Facilities
and Services Chapter is to provide
a policy framework for the City to
manage infrastructure and services,
identify areas for improvement, and
ensure that public utilities, services,
and programs can meet the needs
of the community into the future.
RELATIONSHIP TO STATE LAW
While Public Facilities and Services
is not a mandated element, it
does include a number of topics
that are required to be addressed
in the General Plan according to
State law. State law (Government
Code Section 65302[a]) requires a
general plan to address land uses
for education, public buildings
and grounds, and solid and
liquid waste disposal facilities.
Water supply and demand is also
required to be included in the
General Plan (Government Code
Section 65302[d]) and is addressed
in this chapter. Water quality is
discussed in Chapter 5, Resource
Conservation. This chapter also
establishes a parkland standard to
be maintained in accordance with
the Quimby Act (Government Code
section 66477, part of the California
Subdivision Map Act), which
enables a city to require dedication
of land or fees in lieu of land
dedication for neighborhood and
community parks as a condition of
development approval.
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PUBLIC FACILITIES & SERVICES 6.0
RELATIONSHIP TO OTHER ELEMENTS
This chapter is closely related
to Chapter 2, Land Use and
Economic Development, Chapter
3, Community Character and
Placemaking, Chapter 7, Public
Safety, and Chapter 8, Community
Health and Sustainability. The
Land Use diagram in Chapter 2
establishes existing and potential
locations of different facilities,
including public parks and
community facilities. The buildout
capacity in Chapter 2 can be used
to anticipate the level of public
services that will be needed by
2040. The Community Character
and Placemaking Chapter
addresses the park provision as part
of the public realm. The hazards
to public safety and threats to
public health identified in Chapter
7 also inform the provision of
public services in this element.
Lastly, the availability of parks
and public services are also a key
consideration for public health
in the Community Health and
Sustainability Chapter.
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6.2 PARKS AND RECREATION
PARKS
Parks are a vital part of well-being
in Diamond Bar, providing places
for residents to relax, exercise,
and socialize outdoors while also
providing important gathering
places in the community. This
Chapter provides policies for the
maintenance and provision of
existing and new parkland, and
paints a broad picture of the the
city’s park system. The Parks and
Recreation Master Plan, adopted
by the Diamond Bar City Council in
2011, will help guide implementation
of General Plan policies related to
parks and recreation.
Park Classifications
For planning purposes, parks are
classified by type based on the size,
use, and physical characteristics of
the land.
• Community Parks. Community
Parks are larger parks intended
to accommodate a wide
variety of active and passive
recreation activities for the
community. Amenities provided
in a community park are focused
on meeting the needs of several
neighborhoods or large sections
of the community, and they
allow for group activities and
recreational opportunities
that may not be feasible in
smaller neighborhood parks.
Optimally, Community Parks
range from 20 to 50 acres in
size and serve neighborhoods
within three to five miles of
the park. Where a Community
Park is located in a residential
neighborhood, it also serves
the immediate neighborhood
within three-quarters of a mile
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PUBLIC FACILITIES & SERVICES 6.0
to a mile. Amenities typically
include community buildings,
playground equipment, picnic
areas and picnic shelters,
barbeques, lit sports fields
and courts, public restrooms,
concessions, and on-site
parking. Major events may be
hosted in Community Parks that
attract residents from throughout
the city.
• Neighborhood Parks.
Neighborhood Parks are the
basic unit of the park system
and are typically found in
residential neighborhoods.
They typically range from 5
to 20 acres in size and are
intended to serve surrounding
neighborhoods within a 0.75-
mile to one-mile radius. Ease
of access and walkability to
neighborhoods served are
critical factors in siting and
designing Neighborhood Parks.
Amenities typically include
playgrounds, picnic tables and
shelters, barbeques, sports fields
and courts, public restrooms,
and on-site parking.
• Mini Neighborhood Parks.
Mini Neighborhood Parks are
Neighborhood Parks that range
from a quarter acre to five
acres in size. Mini Neighborhood
Parks may serve neighborhoods
within the same range as
Neighborhood Parks but are
best used to meet limited or
specialized recreation needs.
Mini Neighborhood Parks can
provide landscaped public
use areas, scenic overlooks,
trail linkages, and facilities to
serve a concentrated or limited
population group such as youth
or seniors.
• Specialty Parks. Specialty
Parks provide for a single use or
activity and can include dog
parks, trailheads, skate parks,
and sports complexes. They may
be standalone facilities, or be
located within or adjacent to
other parks.
Park Inventory
Figure 6-1 provides an inventory of
park acreage by classification of
the existing parks and recreation
facilities within the city, including
both public and private facilities.
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-6
Table 6-1 Parkland Inventory (2019)
Park Name Acreage
Community Parks 109.0
Carlton Peterson Park 16.5
Pantera Park1 23.8
Summitridge Park 18.7
Sycamore Canyon Park 2 50.1
Neighborhood Parks 30.9
Diamond Canyon Park 4.3
Heritage Park 3.3
Larkstone Park 6.8
Maple Hill Park 5.5
Paul C. Grow Park 4.5
Ronald Reagan Park 6.5
Sunset Crossing Park (future)3 2.8
Mini Neighborhood Parks 12.0
Longview Park North 1.0
Longview Park South 0.8
Silver Tip Park 2.9
Stardust Park 1.0
Starshine Park 1.7
Summitridge Mini Park 1.3
Washington Park 0.5
Total City Parks 151.9
Other Parks 134.9
Country Park4 134.9
Total Park Land 286.9
Source: City of Diamond Bar, 2019.
Note:
1. Includes Pantera Wildlife Meadow/Dog Park, originally developed as a Specialty
Park.
2. Includes Sycamore Canyon Trail Head Park, originally developed as a Specialty
Park.
3. This will include sports fields and is contiguous with the PONY League Fields. While
the park is smaller than five acres, it is developed as a Neighborhood Park for this area.
4. This is a private park located in the Country Estates neighborhood. While the
neighborhood is a gated community, the park essentially serves as a Community Park
for this development.
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PUBLIC FACILITIES & SERVICES 6.0
Parkland Standard
This Chapter establishes a parkland/
recreational space standard of 5.0
acres per 1,000 residents, consistent
with the Quimby Act. The Quimby
Act allows the City to establish this
standard as a means of requiring
subdivision developers to provide
a dedication of land or in lieu fees
to ensure that the existing ratio
of parkland acres per resident is
maintained even as the number
of residents increases with new
development. As shown in Table
6-1, there are 151.9 acres of public
Community and Neighborhood
parkland in Diamond Bar in 2019,
resulting in a ratio of 2.6 acres of
public parkland per 1,000 residents.
While the Country Park functions
similarly to a Community Park within
the Country Estates neighborhood,
the 134.9 acres of parkland from
Country Park cannot count towards
the parkland ratio as it is a private
amenity. The parkland standard is
established to maintain the ratio
of parkland to residents as the city
continues to grow.
Parkland Distribution
As of 2019, parkland is distributed
fairly evenly among residential
neighborhoods in the city.
However, not every residence is
within walking distance of a park,
and many residents face barriers,
such as highways, steep terrain,
or fences between their homes
and the nearest park. Figure
6-1 shows five- and 10-minute
walksheds, as well as 0.75-mile
neighborhood service radii, for the
city’s Community, Neighborhood,
and Mini Neighborhood parks. As
shown, there are still residential
areas outside of the service radii
of existing parks, and even more
residential areas outside of a
10-minute walking distance. As the
city continues to develop, there will
be opportunities to expand the park
system and improve park access for
all members of the community.
Other Public Recreation Facilities
In addition to parks, Diamond
Bar residents have access to
recreational open space areas and
the County of Los Angeles-operated
Diamond Bar Golf Course. Open
space areas including Sandstone
Canyon and the areas surrounding
Summitridge and Pantera parks are
accessible via the city’s continually
expanding trail network. These
areas constitute hundreds of acres
of City-owned open space that will
be preserved in perpetuity.
The Diamond Bar Golf Course which
is owned and operated by the
County of Los Angeles occupies
172 acres near the western border
of the city. The public golf course
draws users from around the
community and beyond, and offers
18 holes and clubhouse facilities.
As discussed in Chapter 2, Land
Use and Economic Development,
the golf course is covered by
the Community Core Overlay
designation. Should the Golf Course
cease to operate, that designation
would require a master plan for
the entire golf course property to
ensure the orderly and cohesive
implementation of its reuse.
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-8
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EvergreenE.S.
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Quail SummitE.S.
South PointeM.S.
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Peterson Park
Pantera
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Summitridge
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Park
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Park
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Park
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City Parks
Community Park
Neighborhood Park
Mini
Neighborhood Park
Planned Park
Other Recreational Facilities
Sports/
Recreation Facilities
Golf Course
Open Space/
Greenways
Private Park
Existing Trail
Proposed Trail
Class 1 Bikeways
Other Community Facilities
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Schools/
Educational Facilities
Highways
Ramps
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Major Roads
Minor Roads
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Parks Walkshed
5 Minute
Walking Distance
10 Minute
Walking Distance
Parks Service Area
Three-Quarter
Mile Buffer
*Walksheds are calculated only for mini,
neighborhood, and community parks.
Figure 6-1: Existing and Planned Parks
and Recreation Facilities City of Diamond Bar
GENERAL PLAN UPDATEFigure 6-1 Existing and Planned Parks
and Recreation Facilities
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
6.0
6-9
PUBLIC FACILITIES & SERVICES 6.0
TRAILS
Diamond Bar has a trail system
spanning 4.54 miles, summarized
in Table 6-2 and shown in Figure
6-2. Trails offer hikers and cyclists
views of natural landscapes and
the surrounding city. As of 2019,
the Summitridge Trail System is the
most comprehensive trail network
in Diamond Bar and features an
extensive system of interconnected
trails. The Pantera, Peterson, and
Sycamore Canyon Trails span
undeveloped, natural areas of city
parks. Despite the wealth of existing
trails in the city, opportunities still
exist for Diamond Bar to expand
and improve its trail system and
continue to link existing and
future parks and pedestrian and
bicycle facilities through trails. The
City’s 2011 Parks and Recreation
Master Plan identified a number
of measures to improve trail
facilities, including the installation
of mile markers and benches
and programming educational
activities. Additional trail segments
planned within the City as identified
in the Parks and Recreation Master
Plan include the Crooked Creek Trail
and Sandstone Canyon Trails, while
trails planned within the SOI include
the Tonner Canyon Trail and the
Schabarum Trail. These proposed
trails are shown in Figure 6-2.
Complementing this network of
trails with connecting walking and
biking paths along city streets will
provide Diamond Bar residents with
a more complete, accessible trail
network.
RECREATIONAL FACILITIES AND PROGRAMS
Recreational facilities in Diamond
Bar include a variety of privately-
owned facilities such as the
Pony Baseball Fields, swim clubs
and YMCA facilities. In addition,
Diamond Bar utilizes joint-use
agreements with the local school
districts, making school facilities
available for community use under
certain circumstances. The City
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-10
Table 6-2 Existing and Proposed Trail Network (2019)
Existing Trails Miles
Pantera Park Trail 0.60
Peterson Park Trail 0.29
Summitridge Trail 0.98
Summitridge Trail (Alternate Route)0.61
Summitridge Trail (Canyon Route)0.52
Summitridge Trail (Ridge Route)0.62
Sycamore Canyon Park Trail 0.92
Subtotal: Existing Trails 4.54
Proposed Trails Miles
Crooked Creek Trail Head 0.31
Larkstone Park Trail 0.44
Sandstone Canyon Trail Lower 0.79
Sandstone Canyon Trail Upper 1.80
Sandstone Canyon Trail Upper (Alt)0.46
Schabarum Trail (Skyline Extension)9.42
Tonner Canyon Trail 3.84
Subtotal: Proposed Trails 17.06
Total Existing Plus Proposed Trails 21.60
Source: City of Diamond Bar Parks and Recreation Master Plan, 2011, Dyett and Bhatia, 2019.
currently has joint use agreements
with the Pomona Unified School
District (PUSD) and the Walnut
Valley Unified School District
(WVUSD) to use gyms for adult
basketball and volleyball programs,
and with Pomona Unified School
District to use the football field at
Lorbeer Middle School. Diamond
Bar residents have expressed a
desire for additional recreational
facilities, and Joint Use Agreements
represent an effective and cost-
efficient way for the City expand its
options going forward. Additional
joint-use opportunities may arise
from Cal Poly Pomona’s eventual
redevelopment plan of the former
Lanterman site.
City of Diamond Bar recreational
programs include festivals;
summer youth day camps; youth
sports leagues and enrichment
classes; adult sports, fitness, and
enrichment classes; senior activities
and excursions; and toddler
programming. The Diamond
Bar community has expressed a
desire for additional recreational
and given the Diamond Bar
community’s diversity and changing
demographics, it will be important
for the City to actively engage its
residents on recreational facilities
and programming to provide
facilities and programs that suit the
needs and priorities of all residents.
Diamond Bar General Plan 2040 |PUBLIC FACILITIES & SERVICES 6-11
Table 6-2 Existing and Proposed Trail Network (2019)
Existing TrailsMiles
Pantera Park Trail0.60
Peterson Park Trail0.29
Summitridge Trail0.98
Summitridge Trail (Alternate Route)0.61
Summitridge Trail (Canyon Route)0.52
Summitridge Trail (Ridge Route)0.62
Sycamore Canyon Park Trail0.92
Subtotal: Existing Trails4.54
Proposed TrailsMiles
Crooked Creek Trail Head0.31
Larkstone Park Trail0.44
Sandstone Canyon Trail Lower0.79
Sandstone Canyon Trail Upper1.80
Sandstone Canyon Trail Upper (Alt)0.46
Schabarum Trail (Skyline Extension)9.42
Tonner Canyon Trail3.84
Subtotal: Proposed Trails17.06
Total Existing Plus Proposed Trails21.60
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Trails
Existing
2011 Parks and Recreation
Master Plan Proposed Trails
Other Community Facilities
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City Parks
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Highways
Ramps
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City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Figure 6-2: Existing and Proposed Trail Network C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATEFigure 6-2 E xisting and Proposed Trail Network
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-12
PARKS AND RECREATION
GOALS
PF-G-1 Maintain and expand the system of parks,
recreation facilities, open spaces,
and trails that meet the active
and passive recreational needs of
residents of all ages and abilities.
PF-G-2 Provide new parks in concert with new
residential development, and strive to
distribute parkland throughout the City.
PF-G-3 Ensure that new development bears the
costs of new parks and recreation
facilities that are needed to meet any
increase in demand resulting from the
new development, or from which the
new development would benefit.
POLICIES
General
PF-P-1 Periodically update the Parks and
Recreation Master Plan to assess existing
park and recreational facilities, assets,
and deficiencies, and to plan for new
facility locations, programs, and funding.
PF-P-2 Continue to seek public input on parks and
recreation needs and preferences
through surveys, presentation to the
Parks and Recreation Commission,
neighborhood meetings and workshops,
and other community outreach methods
as necessary, such as when siting/
designing new parks, when updating
the Parks and Recreation Master Plan,
when renovating existing parks, etc.
PF-P-3 Identify and pursue funding and financial
resources to acquire land for parks
and to continue providing high
quality maintenance of parks, trails,
and recreational facilities.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
6.0
6-13
GOALS & POLICIES
PF-P-4 Encourage the co-location of new parks
and recreational facilities with
schools, community centers, libraries,
and other public facilities to create
neighborhood focal points that
contribute to neighborhood identity.
PF-P-5 Continue cooperative efforts with the
Walnut Valley and Pomona Unified School
Districts through joint use agreements
for park and recreational facilities.
PF-P-6 Monitor and seek to actively engage in Cal
Poly Pomona’s plans for the redevelopment
of the former Lanterman site, and seek
joint use opportunities for parks and
recreation facilities developed on the site.
Parks & Recreation Facilities
PF-P-7 Endeavor to distribute new parks equitably
throughout Diamond Bar, striving to ensure
that residents are within a ¾-mile radius of
a neighborhood park or community park.
PF-P-8 Develop and maintain a parkland
dedication requirement/in-lieu fee
consistent with the General Plan
standard of five acres per 1,000
residents in Diamond Bar.
PF-P-9 Prioritize public parkland dedication as a
condition of new residential development,
allowing the use of in lieu fees only
where parkland dedication is not
feasible, to ensure a public park system
available to the entire community.
PF-P-10 Should Los Angeles County choose to cease
operations of the Diamond Bar Golf Course
or reduce the area of the Golf Course,
prepare a master plan for development
that includes opportunities for public
parks comprising a range of passive
and active recreational uses to suit the
needs of Diamond Bar residents.
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-14
PF-P-11 Where appropriate, promote the joint
development, use, and maintenance
of parks and open space facilities with
adjacent jurisdictions, the County of Los
Angeles, and the State of California.
PF-P-12 Routinely review existing funding
mechanisms and seek new funding
opportunities to support additional parks
and recreation facilities and programs,
such as State and federal grants, Park
Bonds and property tax assessments,
Community Facility Districts, and Lighting
and Landscape Assessment Districts.
PF-P-13 When planning and designing public
facilities and parks, take into consideration
accessibility, flexible use, adaptability,
energy and water efficiency, ease of
maintenance, and sustainable design
elements that take advantage of the
natural processes of healthy ecosystems,
while preserving historic and cultural
resources and sensitive habitats.
PF-P-14 Preserve existing and future City-owned
recreational open space as recreational
open space in perpetuity.
City-owned recreational open space
includes undeveloped areas of City
parks that are available for passive
recreational use, and portions of designated
open space land that have been
dedicated to the City for use as trails.
See Chapter 2, Land Use and Economic
Development and Chapter
5, Resource Conservation for
additional policies regarding the
preservation of open space.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
6.0
6-15
GOALS & POLICIES
PF-P-15 Prioritize the develop of additional
recreational facilities such as
athletic fields, hard courts, and other
recreational facilities that respond to
citizen needs and preferences.
PF-P-16 Continue to provide programming and
services for seniors, including active
programs, classes, and activities and
outings, adjusting programming based
on needs and preferences, particularly
as Diamond Bar’s residents age.
PF-P-17 Address the recreational needs of all
children and adults, including
persons with disabilities, seniors, and
dependent adults, be addressed in
recreational facility planning efforts.
Trails
PF-P-18 Where feasible, link parks, open spaces, and
regional hiking trails with a trail network.
Incorporate existing trails and bicycle
and pedestrian infrastructure, working
with willing landowners to prioritize land
acquisition where necessary. Where
possible, incorporate landscaping
and enhance natural features.
PF-P-19 Update the Parks and Recreation Master
Plan to include standards for planning,
design, management, and maintenance
of trails and pathways within parks,
preserves, open spaces, and rightsof- way.
Encourage the installation of amenities
such as rest areas, benches, water
facilities, hitching posts and wayfinding
signs serving trails and scenic routes that
adhere to a standard signage palette.
GUIDING POLICIES | 2020-2040 Diamond Bar General Plan Update6-16
PF-P-20 Strive to maintain the Parks and Recreation
Master Plan goal of at least one mile of
recreational trails for each 10,000 persons.
PF-P-21 Seek grants and alternative funding
mechanisms for trail development
and maintenance.
PF-P-22 Promote partnerships with non-profit
organizations to assist in developing and
managing the trails system and providing
community outreach and education.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
6.0
6-17
PUBLIC FACILITIES & SERVICES 6.0
6.3 SCHOOLS AND COMMUNITY FACILITIES
SCHOOLS
Diamond Bar has been fortunate to
be associated with high-performing
schools that have bolstered its
reputation as a family-friendly
community. Schools are thus an
important part of the city’s cultural
landscape and a key factor
in attracting new families and
residents to the city. Diamond Bar
is served by two school districts,
Walnut Valley Unified School District
(WVUSD) and Pomona Unified
School District (PUSD). Grand
Avenue is a rough delineation
between the two districts, with
areas north served by PUSD and
areas south served by WVUSD. The
boundaries of the school districts
are shown in Figure 6-3.
Maintaining strong partnerships with
the two school districts, particularly
in terms of planning for any new
facilities, and supporting the
schools in their continued provision
of excellent education will be an
important consideration as the city
grows.
Walnut Valley Unified School
District
WVUSD serves approximately
13,900 enrolled K-12 students
within portions of the cities of
Diamond Bar, Industry, West
Covina, and Walnut, as well as
portions of unincorporated Los
Angeles County. It is one of the
top performing school districts in
the state, with Diamond Bar High
ranking particularly high. WVUSD
schools within the Diamond Bar city
limits serve 8,008 students in five
elementary schools, two middle
schools, and one high school.
Pomona Unified School District
PUSD serves approximately 23,200
enrolled K-12 students within
portions of the cities of Diamond
Bar, Industry, Pomona, and
Chino Hills, as well as portions of
unincorporated Los Angeles County.
PUSD schools within the Diamond
Bar city limits serve approximately
3,500 students in four elementary
schools, one middle schools, and
one high school.
Interdistrict Transfers
Both WVUSD and PUSD have
experienced trends of declining
enrollment over the last decade
due in part to families in the districts
relocating. WVUSD in particular has
tended to enroll a large number of
students that reside outside of the
school district boundaries thanks
to the District of Choice (DOC)
program, which allows any student
to attend their schools regardless
of the student’s home address
and without seeking permission
of their home districts. Incoming
students that attend WVUSD but
reside in another school district are
referred to as interdistrict transfers
(IDTs). Typically, IDTs are approved
based on an agreement with the
school district of origin, parental
employment within the school
district, or the DOC program. The
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-18
share of IDTs has been increasing
in recent years. Given the high
percentage of IDT enrollment, the
continuation of the DOC program
is a key factor in the long-term
planning of WVUSD schools.
COMMUNITY FACILITIES
Community facilities are public
and private institutions that
support the civic and social needs
of the population. They offer a
variety of recreational, artistic,
and educational programs for all
ages, and often serve as venues
for special public and private
events. As of 2019, community
facilities in Diamond Bar include The
Diamond Bar Center, City Hall, two
community centers, and a County
library, as shown in Figure 6-3.
• Diamond Bar City Hall is located
at 21810 Copley Drive, in a
building the City purchased in
2011 after leasing space across
the street in the South Coast Air
Quality Management District
(SCAQMD) complex for 11 years.
• Diamond Bar Library, a branch
of the Los Angeles County
Library, is housed on the first floor
of the Diamond Bar City Hall
building. This co-location has
allowed the facility to function
as a true community center, with
many programs and activities.
• The Diamond Bar Center,
located in Summitridge Park,
is a 22,500-square-foot facility
containing banquet and
meeting rooms, accommodating
parties of up to 438 people
and up to 1,000 people
for meetings. A pad for a
freestanding building is located
on the grounds of the Diamond
Bar Center, which was once
contemplated as a potential
library site.
• The Heritage Park Community
Center is located at 2900 S Brea
Canyon Road. It accommodates
up to 110 for dining and up to
200 for theatre events, and hosts
classes and workshops.
• The Pantera Park Activity Room
accommodates groups up
to 50 and hosts classes and
workshops.
As the population of Diamond
Bar grows, the need for new and
updated community facilities will
increase. Community members
have already highlighted the
desire for additional facilities to
serve the specific needs of certain
populations, particularly youths
and seniors. While the city’s schools
are strong, the community lacks
a dedicated youth/teen center to
host activities after school hours.
Additionally, there are no exclusive
senior centers in Diamond Bar, in
spite of the city’s growing senior
population, and representatives
from senior groups have expressed
an interest in having a space that
can be accessed at all times, with
activities and meal service.
Diamond Bar General Plan 2040 |PUBLIC FACILITIES & SERVICES 6-19
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Country Park
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Public Facilities
Parks, Recreation & Open Space
School Districts
Pomona Unified
Walnut Valley Unified
Highways
Ramps
Railroads
Major Roads
Minor Roads
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Figure 6-3: Schools and Other Public Facilities City of Diamond Bar
GENERAL PLAN UPDATEFigure 6-3: Schools and Other Public Facilities
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-20
SCHOOLS AND COMMUNITY FACILITIES
GOALS
PF-G-4 Continue to provide residents of all ages
and abilities with access to high quality
local educational facilities and learning
opportunities in cooperation with the
Walnut Valley and Pomona Unified School
Districts (WVUSD and PUSD, respectively),
the Los Angeles County library system,
and community organizations.
PF-G-5 Continue to provide and expand
opportunities for all residents to
gather, interact, exchange ideas, and
establish and realize common goals.
POLICIES
Schools
PF-P-23 Coordinate land use planning with the
planning of school facilities. Work with the
WVUSD and PUSD to monitor demographics
and housing and enrollment trends,
and work with the school districts from
the early stages of area-wide planning
and school site selection processes,
reserving school sites to accommodate
school district needs as necessary.
PF-P-24 Continue to support the Walnut Valley and
Pomona Unified school districts’
adult education programs.
Community Facilities
PF-P-25 Support and cooperate with Los Angeles
County’s efforts to ensure the adequate
provision of library services.
PF-P-26 Periodically seek citizen input on learning
needs and arts and cultural interests
through surveys, workshops, and other
community outreach methods, and strive to
respond to these needs and interests with
corresponding programming and services.
2020-2040 Diamond Bar General Plan Update | GUIDING POLICIES
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GUIDING POLICIES
PF-P-27 As resources become available, explore
and pursue the feasibility of developing
dedicated community centers
and programming in Diamond Bar
for teens, youth, and seniors.
PF-P-28 Continue sponsoring and promoting
events and cultural activities that bring
the community together in different
locations throughout the city.
PF-P-29 Encourage the development of privately-
owned public spaces and plazas in private
commercial and office complexes.
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-22
6.4 UTILITIES
WATER
A fundamental yet long-term
constraint on development is
availability and quality of water.
The City of Diamond Bar relies
on Walnut Valley Water District
(WVWD) to provide reliable water
supplies throughout the city. Nearly
all water supplies are imported
due to a limited availability of
local groundwater. Imported
water supplies are expected to
remain attainable for at least three
years, and projected supplies
are expected to meet projected
demands under single dry-year
and multiple dry-year conditions
as described in the Metropolitan
Water District of Southern California
2015 Urban Water Management
Plan, which projects demand over
a 20-year period through 2035.
Drought conditions will continue
to strain water supply available
to WVWD and the city as they do
throughout southern California.
Thus a “drought-proof” recycled
water system is maintained for use
by parks and school properties
to relieve demand on WVWD’s
potable water system. WVWD is
proactive in addressing water supply
constraints and continues to invest
in groundwater facilities. Looking
ahead, the City of Diamond Bar
can supplement WVWD’s efforts by
acting as a collaborative partner
in the WVWD’s assessment of water
supply and projected demand, and
by encouraging smart water use
amongst Diamond Bar residents.
Water Supply
WVWD imports all potable water
from the Metropolitan Water District
of Southern California (MWD).
WVWD currently has projects
underway that will produce
groundwater from the San Gabriel
Basin, Central Basin, and Six Basins
to supplement potable water
supplies. A description of available
water supplies is provided below.
Imported Water
MWD obtains surface water from the
Colorado River and from Northern
California via the Colorado River
Aqueduct and the California
Aqueduct respectively. WVWD
purchases water through MWD’s
designated wholesale agency,
the Three Valleys Municipal Water
District (TVMWD). WVWD assumes
that imported water supply volumes
will increase through 2035 at the
same rate as SCAG’s reported
population growth of 0.7 percent,
with incremental reductions
based on projected groundwater
production and supply.
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PUBLIC FACILITIES & SERVICES 6.0
Groundwater
WVWD currently operates six
groundwater production facilities
that supply the recycled water
system. This groundwater is not
potable as it contains high levels of
total dissolved solids and nitrates.
The following three recent projects
allow the WVWD to produce
potable groundwater, thereby
reducing the need for imported
water in the future:
• The La Habra Heights County
Water District Pipeline Project,
completed in 2014, delivers up to
1,000 acre-feet of potable water
per year from the Central Basin
to WVWD. This project includes
an inter-connection to the La
Habra Heights County Water
District system.
• The California Domestic Water
Company Project, completed in
2016, consists of a new pipeline
and pump station project that
will connect to the California
Domestic Water Company
system. Annual deliveries to
WVWD consist of 2,500 acre-feet
of potable water. Water stored in
the Main San Gabriel Basin will
supplies potable water for this
project.
• Production from Six Basins
will supply WVWD with
approximately 928 acre-feet of
potable water per year upon
completion of the Pomona Basin
Regional Groundwater Project.
This project includes reactivating
an existing well and constructing
one new well, and is which is
anticipated to be complete by
the end of 2019.
Recycled Water
WVWD owns, operates, and
maintains a recycled water system
that provides irrigation water to
customers throughout its service
area, including the City of Diamond
Bar. The County Sanitation District’s
Pomona Water Reclamation Plant
supplies recycled water to WVWD
for irrigating large landscape
areas such as parks, golf courses,
greenbelts, and school grounds.
Future uses will generally fit these
categories, with potential demands
for toilet flushing in high-rise
buildings and industrial use. Local
groundwater supplies may also
help WVWD expand the current
recycled water system. This system
is completely separate from the
potable system and helps reduce
potable water demand.
As of 2019, however, recycled
water supplies are maxed out
during peak summer months.
Therefore, large-scale expansion
of the system is not feasible until
additional recycled water supplies
become available. Moving
forward, the City of Diamond Bar
can act as an important partner
in the encouragement of sourcing
additional recycled water supplies
and usage.
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-24
Future Water Projects
The Cadiz Valley Water
Conservation, Recovery and
Storage Project will allow TVMWD
to supply WVWD with water from a
renewable aquifer in the eastern
Mojave Desert. Approximately five
percent of the aquifer’s water will
be pumped over the 50-year life
of the project. This will prevent loss
of water to evaporation, provide
a new water supply, and create
a groundwater bank for Southern
California water providers.
Water System Infrastructure
WVWD’s service area encompasses
approximately 29 square miles
of the San Gabriel Valley. The
service area includes the City of
Diamond Bar, portions of the cities
of Walnut, West Covina, Pomona,
and a section of unincorporated
Rowland Heights. WVWD’s service
area is primarily residential, with
most commercial and industrial uses
located in the City of Industry.
Potable Water
In 2019, the WVWD potable water
distribution and storage system
consists of the following facilities:
• 23 water reservoirs;
• 9 pump stations;
• 29 pressure regulating stations;
• 238.6 miles of distribution and
transmission pipeline; and
• 4 connections for importing
water.
Eight pressure zones are required to
provide adequate water pressure to
all consumers. Improvements and
upgrades are in progress, including
the development of a disinfectant
residual control system to enhance
and maintain water quality. An
emergency power program is in
process that will ensure availability
of potable water after emergencies
or power outages.
Recycled Water
In 2019, WVWD’s recycled water
distribution and storage system
consists of the following facilities:
• 2 water reservoirs;
• 2 pump stations;
• 6 wells; and
• 8.37 miles of distribution pipeline.
Communities within WVWD’s service
area are supportive of efforts to
expand the recycled water system.
WVWD has funded installation
of recycled water distribution
mains and meters. Installation
of new meters is required for all
development projects that have a
potential for recycled water use.
Due to topographical constraints,
as of 2019 recycled water is only
available on the western side
of Diamond Bar. The potential
delivery of recycled water to the
eastern side of the city, pending
the availability of supply, represents
an opportunity to expand recycled
water usage in the future.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
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PUBLIC FACILITIES & SERVICES 6.0
Water Use
Diamond Bar’s potable water use
since 1993 has ranged from 7,077 to
13,188 acre-feet per year. Water use
has generally declined during this
time despite a continual increase
in the total number of accounts, as
shown in Table 6-3. However, usage
is expected to increase through
the 2035 WVWD system buildout, as
shown in Table 6-3.
A breakdown of all water uses
from the 2015 UWMP show single
and multi-family residences use
a majority of potable water (80
percent in 2015), followed by
commercial properties (5.7 percent
in 2015).
Table 6-3 Water Usage
Year Total Accounts Total Water Usage (Acre-Feet per Year)
1993 11,772 12,681
1995 11,833 10,975
2000 11,971 13,188
2005 12,422 12,521
2010 12,426 9,260
2015 12,432 7,077
2020 (Projected)Not Available 8,281
2035 (Projected)Not Available 9,179
Source: Walnut Valley Water District
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-26
Table 6-4 2015 Projected Water Supply vs. Water Usage,
Walnut Valley Water District
Year Projected Water Usage (Acre-Feet per Year)
Projected Water Suply (Acre-Feet per Year)
2020 19,357 20,074
2025 20,035 20,777
2030 20,736 21,505
2035 21,462 22,258
Source: Walnut Valley Water District 2015, Urban Water Management Plan, June 2016.
Water Supply Vs. Demand
A comparison of projected water
supplies and usage at regular
intervals is only available for
WVWD’s total service area and is
shown on Table 6-4. According to
WVWD staff, existing and planned
facilities are capable of maintaining
a sufficient level of service for
projected population growth in the
city.
Water Conservation
Water conservation measures
are implemented and enforced
through several WVWD-run
measures. WVWD’s Ordinance No.
06-09-07 establishes progressive
water reductions during drought
conditions.
The Water District also implements
Demand Management Measures
to enforce responsible water use.
Wasteful consumption, including
excessive runoff and washing hard
or paved surfaces, is prohibited.
Notified water users have five days
to remedy any wasteful practices.
Failure to comply may result in a
disconnection of service. Other
incentives to conserve water include
rebate programs for rain barrels and
high-efficiency washing machines.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
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PUBLIC FACILITIES & SERVICES 6.0
WASTEWATER
Los Angeles County provides
wastewater collection and
treatment services under contract
to the City of Diamond Bar. The
Los Angeles County Public Works
Department (LACPWD) provides
operation and maintenance
services on the local collection
system, while Los Angeles County
Sanitation District (LACSD) provides
operation and maintenance
services on the trunk sewers and
wastewater treatment services.
The city and surrounding areas fall
under the LA County Sanitation
District No. 21. While the system
is generally in good order, as
described below, there has not
been an area-wide sewer study
completed in the last 10 years that
identifies all deficiencies within the
City’s sewage infrastructure system.
Sanitary Sewer System
Infrastructure
The local collection system
contains 11 pump stations and 162
miles of sewer mains within the
city. According to City Staff, the
local collection system is in good
standing with no known major
system deficiencies.
Los Angeles County Public Works
The local collection system is shown
on Figure 6-4. The local system
of sewer lines and pump stations
feed two trunk sewer lines that
convey wastewater to a LACSD
treatment facility. LACPWD has
been completing systematic annual
audits of the collection system,
including closed-circuit television
(CCTV) inspections of sewer lines,
and manhole and pump station
inspections. Any structural or
maintenance deficiencies in the
sewer system identified during
the audit are reported with a
recommended repair. In 2015,
no sewer capacity issues were
identified. However, the City
regularly pumps wastewater at the
intersection of Clear Creek Canyon
Road and Diamond Bar Boulevard
to overcome system deficiencies,
which may warrant further
investigation in the future.
The City and LACPWD have been
effective at keeping the number
and total volume of sanitary system
overflows (SSOs) within the city
below the Statewide median, with
only three SSOs reported in each of
the last three years. In addition, the
City rarely receives complaints from
citizens regarding wastewater and
SSO. The SSOs are typically related
to debris, root intrusion, and/or fats/
oil/grease causing the overflow
issues. In addition, there are
occasional SSOs related to pump
station failures.
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-28
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Sphere of Influence
County Boundary
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MILES
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City of Diamond Bar 2019; Dyett & Bhatia, 2019Ri versideMetrolinkLineFigure 6-4: Existing Sanitary Sewer System City of Diamond Bar
GENERAL PLAN UPDATEFigure 6-4: Existing Sanitary Sewer System
Diamond Bar General Plan 2040 |PUBLIC FACILITIES & SERVICES 6-29
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MILESSource: City of Diamond Bar 2019; Dyett & Bhatia, 2019RiversideMetrolinkLin eFigure 6-5: Existing Storm Drain System C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATEFigure 6-5: Existing Storm Drain System
PUBLIC FACILITIES & SERVICES |Diamond Bar General Plan 20406-30
Los Angeles County Sanitation
District
LACSD maintains two trunk sewer
lines that originate south of SR-60
and west of SR-57. These lines
convey wastewater to a County
treatment facility outside city
limits, also maintained by the
LACSD. As new development
occurs, the LACSD requires the
new developments to annex into
its service area for operation,
maintenance, and treatment
services. Service fees fund required
upgrades to trunk sewer lines or
treatment plant capacity.
STORMWATER
The Los Angeles County Flood
Control District (LACFCD) owns
and maintains all major flood
control channels in Diamond
Bar. In addition, a majority of the
storm drain system within the city
was formally transferred through
resolution to LACFCD, which
maintains complete ownership
and maintenance of the system.
However, some portions of the
existing system were never
transferred to LACFCD. This has
resulted in ownership disputes
with LACPWD, who provides
maintenance only for said portions
and makes no claims toward
ownership. Stormwater quality is the
responsibility of the City. While the
system is generally in good order, a
master drainage plan, identifying
all deficiencies within the City’s
drainage infrastructure system, has
not been completed.
Storm Drainage System
Infrastructure
The city’s storm drain system can be
seen on Figure 6-5. The local storm
drain system generally consists
of a series of catch basins and
reinforced concrete pipes/boxes
that convey stormwater runoff to
other major flood control channels.
The local storm drain system
conveys water to one of three major
flood control channels, the San
Jose Creek, Diamond Bar Creek,
and the Brea Canyon Channel.
These major flood control channels
are owned and maintained by the
LACFCD. According to City staff,
the local storm drain system is in
good standing with no known major
system deficiencies.
Diamond Bar General Plan 2040 | PUBLIC FACILITIES & SERVICES
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PUBLIC FACILITIES & SERVICES 6.0
SOLID WASTE
Diamond Bar is contracted with
Waste Management, Inc. and
Valley Vista Services for solid waste,
compost and recycling collection,
bulky item pick-up, and leaf and
limb pick-up as of 2019. Hazardous
waste is typically managed through
Los Angeles County facilities, where
Diamond Bar residents can dispose
of hazardous waste items such as
batteries, herbicides, pesticides,
pool cleaners, batteries, and
electronics.
Trash can be diverted away from
landfills through strategies such as
recycling, composting, reuse, and
waste reduction. Waste reduction
and diversion can in turn reduce
greenhouse gas emissions, methane
production, and the burden on
landfills to accommodate waste.
In recognition of this, recent State
law has become more important.
Assembly Bill 1826, singed in 2014,
requires businesses and multifamily
complexes of five or more units
are to recycle their organic waste,
depending on the amount of waste
they generate per week. Organic
waste includes food waste, green
waste, landscape and pruning
waste, nonhazardous wood waste,
and non-food-soiled paper. In
order to meet or exceed these
state mandates, Diamond Bar
partners with Los Angeles County
and participates in the countywide
Integrated Waste Management
Plan.
OTHER UTILITIES
Utilities such as electricity, natural
gas, and telecommunications,
including broadband internet
service, are considered common
elements of contemporary life. It is
necessary to ensure these services
are available and adequate to
meet the demands of all Diamond
Bar residents and businesses. Rising
demand associated with population
and employment growth will
necessitate additional facilities. It is
important that these new facilities
and services be provided in a
manner that minimizes impacts on
the built and natural environments
and on the health and safety
of Diamond Bar residents and
businesses.
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-32
UTILITIES
See Chapter 5: Resource Conservation for policies
regarding water conservation.
GOALS
PF-G-6 Ensure that public facilities and services,
including water, wastewater, sewage,
electricity, natural gas, and solid waste,
are provided in a safe, efficient, and
timely manner to meet the current
and future needs of the city.
PF-G-7 Maintain adequate systems for potable
water supply and distribution to meet the
current and future needs of the city.
PF-G-8 Work with providers to deliver the best
telecommunications service possible,
including broadband internet, to Diamond
Bar residents, businesses, and visitors.
POLICIES
Facilities
PF-P-30 Require, when appropriate, the construction
of water, sewer, drainage, and other
necessary public facilities, and
encourage storm water capture prior to
or concurrent with new development.
PF-P-31 Require, when appropriate, project sponsors
to provide all necessary infrastructure
improvements, including the pro rata
share of system-wide improvements.
PF-P-32 Maintain a development fee structure that
ensures, when appropriate, that costs
for new capital facilities and expansion
of existing facilities necessitated by
the approval of new development or
intensification of existing development are
funded by the proponents or beneficiaries
of projects, in proportion to the demand
created by the development.
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GOALS & POLICIES
PF-P-33 Ensure adequate funding and planning for
needed public services and
facilities in coordination with the
Capital Improvement Program.
PF-P-34 Continue to communicate major
development plans with utility
companies and coordinate planning
of extension of necessary facilities.
Water and Wastewater
PF-P-35 Support the Walnut Valley Water District
(WVWD) in efforts to assess the condition
of water distribution and storage
systems within Diamond Bar and plan
for refurbishments as needed.
PF-P-36 Support and take part in the WVWD’s efforts
to develop future plans to expand
the use of recycled water within
Diamond Bar as additional recycled
water supplies become available.
PF-P-37 As opportunities arise, work with the Los
Angeles County Public Works Department
(LACPWD) and Los Angeles County
Sanitation District (LACSD) to ensure
that wastewater treatment conveyance
systems and treatment facility
capacity is available to serve planned
development within Diamond Bar.
PF-P-38 Continue to monitor and assess wastewater
and sewer system operations to identify and
subsequently address system deficiencies.
PF-P-39 Pursue the transfer of ownership of all
portions of the storm drain system within
Diamond Bar to the Los Angeles County
Flood Control District (LACFCD).
PUBLIC FACILITIES & SERVICES | Diamond Bar General Plan 20406-34
PF-P-40 As resources become available, seek
cooperation with the LACFCD to
complete a drainage master plan for
Diamond Bar with a view to identifying
any deficiencies within the city’s
drainage infrastructure system, and
update it periodically, as needed.
Communications
PF-P-41 When resources are available, consider
developing a plan for the improvement
and expansion of the communications
infrastructure network to address
existing infrastructure needs and
development opportunities, and provide
cost effective and efficient solutions,
including exploring the possibility of
using City property and rights-of-way
for communication infrastructure sites.
PF-P-42 Encourage the deployment of broadband
to as many areas in the community and
key transportation corridors as possible and
pursue additional providers to increase
competition and improve quality of service.
Protection from hazards is an
essential service of public
agencies and a critical priority
for the City of Diamond Bar,
particularly given the unique
environmental, seismic, and
topographic conditions of the
city.
PUBLIC SAFETY 7.0
PUBLIC SAFETY | Diamond Bar General Plan 20407-2
7.1 INTRODUCTION
The purpose of the Public Safety
Chapter is to identify the natural
and man-made public health and
safety hazards that exist within the
city, and to establish preventative
and responsive policies and
programs to mitigate their potential
impacts. The Public Safety Chapter
also addresses noise and serves to
limit the exposure of the community
to excessive noise levels. The Public
Safety Chapter addresses and
satisfies the requirements of both
the required Safety and Noise
Elements of a General Plan.
RELATIONSHIP TO STATE LAW
Government Code Section 65302(g)
requires each California city to
include within its General Plan a
Safety Element that addresses the
protection of the community from
any unreasonable risks associated
with the effects of seismic and other
geologically-induced hazards,
flooding, and fires. The Safety
Element is required to include
mapping of known seismic and
geological hazards, and it must
identify flood hazards and urban
and wildland fire hazards. Where
applicable, it must also address
evacuation routes, peak load water
supply requirements, minimum
road widths, and clearances
around structures. The Safety
Element is also required to address
the protection of the community
from unreasonable risks through
fire protection, law enforcement,
emergency preparedness, and the
City’s Local Hazard Mitigation Plan.
Government Code Section 65302(f)
requires each California city and
county to include within its general
plan a Noise Element that analyzes
and quantifies noise levels and the
extent of noise exposure in their
jurisdictions from the following
sources:
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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PUBLIC SAFETY
• Highways and freeways;
• Primary arterial and major local
streets;
• Passenger and freight online
railroad operations and ground
rapid transit systems;
• Commercial, general aviation,
heliport, helistop, and military
airport operations, aircraft
overflights, jet engine test stands,
and all other ground facilities
and maintenance functions
related to airport operation;
• Local industrial plants, including,
but not limited to, railroad
classification yards; and
• Other ground stationary noise
sources identified by local
agencies as contributing to the
community noise environment.
The Noise Element is required to
map noise level contours such
that it may be used as a basis
for land use decisions. It must
include implementation measures
and possible solutions to existing
and foreseeable noise problems.
Furthermore, the policies and
standards of the Noise Element must
be sufficient to serve as a guideline
for compliance with sound
transmission control requirements.
RELATIONSHIP TO OTHER ELEMENTS
The Public Safety Chapter is
correlated with Chapter 2, Land
Use and Economic Development,
Chapter 4, Circulation, and
Chapter 6, Public Facilities and
Services. Chapter 2, Land Use and
Economic Development includes
consideration of hazards in land
use designations and their density
standards, and outlines the desired
land use pattern in Diamond
Bar to promote public safety
through ensuring compatible uses.
Policies in Chapter 2 also address
issues of land use compatibility,
which is closely related to noise
compatibility as discussed in this
chapter. This element is related
to Chapter 4 as the design of the
transportation system is connected
to the adequate and efficient
delivery of emergency services.
This element also addresses the
relationship between transportation
facilities and noise. Lastly, policies
related to the provision of public
utilities in Chapter 6, Public Facilities
and Services relate to safety issues
and services in this element.
PUBLIC SAFETY | Diamond Bar General Plan 20407-4
7.2 SEISMIC AND GEOLOGIC HAZARDS
GEOLOGIC HAZARDS
Geologic hazards include soil
erosion and landslides, subsidence,
and expansive soils. Soil properties
have significant bearing on
geologic hazards. Local soils in
the Planning Area are largely the
result of bedrock materials that
have weathered, consisting of a
variety of sandstones, shales, and
siltstones. The natural canyons in
the area contain alluvial, or stream-
carried materials, while artificial fill
is present in areas that have been
developed.
Erosion and Landslides
Soil erosion is the process by which
soil materials are worn away and
transported to another area, either
by wind or water. Erosion is a natural
process that occurs over time, but
over the long-term it can impact
the stability of landforms and
structures in sloped or steep areas.
Landslides, also referred to as slope
failures, include many phenomena
that involve the downslope
displacement and movement
of material, either triggered by
static (i.e., gravity) or dynamic
(i.e., earthquake) forces. Exposed
rock slopes may undergo rockfalls,
rockslides, or rock avalanches, while
soil slopes may experience shallow
soil slides, rapid debris flows, and
deep-seated rotational slides.
Landslide-susceptible areas are
characterized by steep slopes,
downslope creep of surface
materials, and unstable soil
conditions. On slopes greater than
30 percent, these soils are subject to
rapid runoff and present moderate
to high erosion hazards. Slides are
more likely to occur during the
wet season and in areas of high
groundwater and saturated soils, or
in post-wildfire areas. As shown in
Figure 7-1, steep slopes are common
throughout the Planning Area, in
areas designated for development
and frequently abutting residential
land uses. Managing erosion and
landslide hazards will involve
approaches that help residents
and decision-makers understand
the particular potential risks facing
individual projects and pursuing
mitigation to reduce risks to an
acceptable level.
Expansive soils
Expansive soils have shrink-swell
capacity, meaning that they may
swell when wetted and shrink
when dried. Expansive soils can
be a hazard for built structures,
and may cause cracks in building
foundations, distortion of structural
elements, warping of doors and
windows, and plumbing breakages.
The higher the clay content of
a soil, the higher its shrink-swell
potential. Expansive soil conditions
are pervasive in the city, and
well-documented in geotechnical
reports. Although some soil
movement is unavoidable over
time, solutions can be engineered
to established factors of safety.
Subdivisions, primarily in The
Country, do have Restricted Use
Areas (RUAs) recorded on the maps,
usually back slopes, that were not
evaluated for constructability.
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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PUBLIC SAFETY
SEISMIC HAZARDS
Although the Planning Area
contains no active faults, it is in
a seismically active region with
several major active faults located
nearby (Figure 7-2). The San Andreas
Fault Zone, which has the greatest
potential to cause damage in the
region, is 26 miles northeast of the
city. The Planning Area, however,
is at greater risk from the active
local faults of Whittier, San Jose,
Sierra Madre, and San Gabriel.
Given the proximity to active fault
lines, potential for seismic hazard in
the Planning Area is high. Seismic
hazards include groundshaking,
surface rupture, and ground
failure. Due to the nature of seismic
hazards, exposure to seismic risks
cannot be completely eliminated;
however, they can be reduced
through adherence to State building
codes and other local regulations.
Groundshaking and Surface
Rupture
Groundshaking can be caused by
activity along faults in the broader
region. Effects of groundshaking
can vary depending on the
magnitude of the earthquake,
distance from the fault, depth,
and type of geologic material.
Severe groundshaking can result in
damage to or collapse of buildings
and other structures. Surface rupture
is the breaking of the ground along
a fault during an earthquake and
is primarily a risk for areas overlying
active faults. As there are no active
faults in the Planning Area, risk of
surface rupture is low.
Ground Failure
Ground failure can occur as a
result of seismic activity, taking
the form of liquefaction, lateral
spreading, subsidence, or
landslide. Liquefaction is the rapid
transformation of saturated, loose,
fine-grained sediment (such as silt
and sand) into a fluid state as a
result of severe vibratory motion.
Lateral spreading refers to a type of
landslide that form on gentle slopes
an has rapid fluid-like movement
caused by liquefaction. Factors
determining the potential for
liquefaction and lateral spreading
are soil type, the level and duration
of seismic ground motions, the
type and consistency of soils, and
depth to groundwater. Figure 7-3
shows areas identified by the State
as having potential for liquefaction
due to past occurrences or the
presence of certain conditions. Note
that there may be additional areas
not shown on the map that may be
susceptible to liquefaction, where
risks may only be determined as
part of a site-specific investigation.
Earthquakes can also trigger
subsidence or landslides; if the
earthquake is strong, this can occur
even in areas of moderate or even
low susceptibility. Figure 7-3 shows
areas identified by the State of
California as potentially susceptible
to earthquake-induced landslides
due to previous occurrence or the
presence of certain conditions. Note
that there may be additional areas
not shown on the map that may be
susceptible to landslide, where risks
may only be determined as part of
a site-specific investigation.
PUBLIC SAFETY | Diamond Bar General Plan 20407-6
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Slopes over 30 Percent Highways
Ramps
Major Roads
Local Roads
Railroads
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.7 1.40.35
MILES
Source: Los Angeles County GIS Data Portal, 2016; Natural
Resources Conservation Service, USDA, 2016;
City of Diamond Bar, 2019; Dyett & Bhatia, 2019Riv ersideMetrolinkLineFigure 7-1: Steep Slopes City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-1 Steep Slopes
Diamond Bar General Plan 2040 | PUBLIC SAFETY 7-7
LOS ANGELES
COUNTY
ORANGE COUNTY
SAN BERNARDINO
COUNTYIndianHillfault CentralAvenuefault
Elsinore fault zone, Whittier section (Whittier fault)
S a n J o s e f a u l t
W alnut Creek faultFault
Alquist-Priolo
Earthquake Fault Zones
City of Diamond Bar
Sphere of Influence
County Boundary
0120.5
MILES
Source: Esri, 2019; California Geological Survey (CGS), 2018;
City of Diamond Bar, 2019; Dyett & Bhatia, 2019
Figure 7-2: Regional Faults City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-2 Regional Faults
PUBLIC SAFETY | Diamond Bar General Plan 20407-8
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Earthquake Induced Landslide Zones
Highways
Ramps
Major Roads
Local Roads
Railroads
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.7 1.40.35
MILES
Source: Seismic Hazard Zones, Earthquake Zones of Required Investigation, 199,
California Geological Survey (CGS), California Department of Conservation (DOC);
Los Angeles County GIS Data Portal, 2016; City of Diamond Bar, 2019;
Dyett & Bhatia, 2019 RiversideMetrolinkLineLiquefaction Zones: Areas where historical occurrence of liquefaction,
or local geological, geotechnical and ground water conditions indicate
a potential for permanent ground displacements such that mitigation
as defined in Public Resources Code Section 2693(c) would be
required.
Landslide Zones: Areas where previous occurrence of landslide
movement, or local topographic, geological, geotechnical and subsurface
water conditions indicate a potential for permanent ground
displacements such that mitigation as defined in Public Resources Code
Section 2693(c) would be required.
Figure 7-3: Liquefaction and Landslide Hazards City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-3 Liquefaction and Landslide Hazards
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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GOALS & POLICIES
SEISMIC AND GEOLOGIC HAZARDS
See Chapter 2: Land Use and Economic Development
Element and Chapter 4: Resource Conservation Element
for additional policies regarding hillside protection and
management.
GOALS
PS-G-1 Partner with the Los Angeles County Fire
and Sheriff’s Departments in community
education efforts aimed at preventing
potential loss of life, physical injury,
property damage, public health hazards,
and nuisances from seismic ground
shaking and other geologic hazards
such as landslides and mudslides.
POLICIES
PS-P-1 Require new emergency facilities subject to
City land use regulations and permitting
requirements, including, but not limited to,
paramedic services, hospitals, ambulance
services, and emergency operations
centers be designed to withstand
and remain in operation following the
maximum credible earthquake event.
PS-P-2 Require areas identified as having
significant liquefaction potential (including
secondary seismic hazards such as
differential compaction, lateral spreading,
settlement, rock fall, and landslide) to
undergo site-specific geotechnical
investigation prior to development and
to mitigate the potential hazard to a
level of insignificance or, if mitigation
is not possible, to preserve these areas
as open space or agriculture.
Figure 7-3 shows areas where historical
occurrence of liquefaction, or
local geological, geotechnical,
and groundwater conditions
indicate a potential for permanent
ground displacements.
PUBLIC SAFETY | Diamond Bar General Plan 20407-10
PS-P-3 Periodically update the grading standards to
supplement the State and local building
and construction safety codes with
detailed information regarding rules,
interpretations, standard specifications,
procedures requirements, forms, and other
information applicable to control excavation,
grading, and earthwork construction,
and provide guidelines for preparation
of geotechnical reports in the city.
PS-P-4 Carry out a review of City-owned critical
facilities that may be vulnerable to
major earthquakes and landslides and
develop programs to upgrade them.
PS-P-5 Develop a City-based public awareness/
earthquake preparedness program to educate
the public about seismic hazards and what
to do in the event of an earthquake.
PS-P-6 Prevent and control soil erosion and
corresponding landslide risks on public
property and in conjunction with new
private development through hillside
protection and management.
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PUBLIC SAFETY
7.3 FLOOD HAZARDS AND PROTECTION
DRAINAGE
The Planning Area is almost entirely
encompassed by the San Gabriel
River Basin, which spans 713 square
miles across Los Angeles and
Orange counties. As shown in Figure
7-4, the Planning Area drains into
four subbasins of the San Gabriel
River Basin. The northern half of the
city drains primarily into San Jose
Creek, partially via Diamond Bar
Creek. Most of the southern half of
the city, as well as the SOI, drains
into Brea Canyon Creek. Small
areas in the northeast of the city
are within the Santa Ana River Basin,
draining locally into Chino Creek.
FLOODING
The Federal Emergency
Management Agency (FEMA) flood
map identifies flooding hazards
of various intensities. As shown in
Figure 7-4, there are two portions of
the Planning Area that are within
the 100-year flood zones, which are
areas having a 1.0 percent chance
of flooding in a given year. The only
100-year flood zone within the city
limits lies near the intersection of
Brea Canyon Road and Lycoming
Street, along the Reed Canyon
Channel. Another 100-year flood
zone runs through Tonner Canyon
Creek in the SOI. Measures that
can minimize flooding hazards
include the preservation of
open space; protecting natural
floodplain functions; regulating
development in the floodplains;
addressing flood-prone properties
through acquisition, relocation,
or protection; and improving
maintenance of the drainage
system on a citywide basis as well
as related to specific development
projects.
PUBLIC SAFETY | Diamond Bar General Plan 20407-12
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(1% Annual Chance Flood Hazard)
500 Year Floodplain
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Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.7 1.40.35
MILES
Source: Los Angeles County GIS Data
Portal, 2016; FEMA's National Flood Hazard Layer, FEMA, 2016;
City of Diamond Bar 2016; Dyett & Bhatia, 2019Ri versideMetrolinkLineFigure 7-4: Flood Zones City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-4 Flood Zones
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GOALS & POLICIES
FLOOD HAZARDS AND PROTECTION
See Chapter 6: Public Facilities and Services for
additional policies regarding water and wastewater
facilities and relevant plans.
GOALS
PS-G-2 Implement measures aimed at preventing
the potential for loss of life, physical injury,
property damage, public health hazards,
and nuisances from the effects of a 100-
year storm and associated flooding.
POLICIES
PS-P-7 Work with the Federal Emergency
Management Agency (FEMA) as needed to
ensure that the City’s floodplain information
is up to date with the latest available
hydrologic and hydraulic engineering data.
PS-P-8 Continue to implement flood control
programs, such as the City’s Grading
and Floodplain Ordinances, that reduce
flood hazards to comply with State
flood risk management requirements.
PS-P-9 Consider the impacts to health and safety
from potential flooding on future
development in flood-prone areas,
including those identified as being within
the 100- or 500-year floodplains. Require
installation of protective structures or other
design measures to protect proposed
building and development sites from
the effects of flooding in these areas.
Figure 7-4 shows flood zones in and
around the Planning Area based on
FEMA’s 2016 flood hazard data.
PS-P-10 Ensure that a drainage study has been
completed by a qualified engineer
as a prerequisite to new development
or the intensification of existing
development, certifying that the proposed
development will be adequately
PUBLIC SAFETY | Diamond Bar General Plan 20407-14
protected, and that implementation
of the development proposal will not
create new downstream flood hazards.
PS-P-11 Use the drainage master plan developed in
coordination with the Los Angeles County
Public Works Department to assess existing
and future flood control needs and related
improvements within Diamond Bar.
PS-P-12 As part of the Capital Improvement
Program, consider and incorporate
flood control improvements identified in
the drainage master plan that specifies
funding and timing of prioritized
improvements. Coordinate the City’s
Capital Improvement Program with
planned County improvements.
PS-P-13 As resources become available, reduce the
flooding impact of a storm event by
enhancing the city’s green infrastructure
system to complement the gray
infrastructure system where feasible.
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PUBLIC SAFETY
7.4 FIRE HAZARDS
URBAN FIRES
Urban fires are fires that begin in
urban centers. They are typically
localized, but have the potential
to spread to adjoining buildings,
especially in areas where homes
and/or business facilities are
clustered close together. Other
factors affecting urban fire risk
and relative likelihood of loss of
life or property include building
age, height and use, storage of
flammable material, building
construction materials, availability
of sprinkler systems, and proximity
to a fire station and hydrants. Urban
fire risk in the city is mitigated in a
number of ways, including through
the enforcement of updated
building and fire codes and the
involvement of the Los Angeles
County Fire Department in the
development review process. Fire
services are discussed further in
Section 7.6: Public Safety Services.
WILDLAND FIRES
Wildland fires occur in rural or
heavily vegetated areas where
abundant surface fuels are
available to sustain a fire. Wildland
fires that occur in the wildland-
urban interface (WUI)—areas where
undeveloped wildlands intermix
with or transition into developed
land—have the potential to greatly
impact nearby structures and cities.
Due to its setting amidst vegetated
open space areas to the south and
east, and the presence of open
space areas interspersed among
urban development, Diamond Bar is
at risk from wildland fires.
Fire Threat and Fire Hazard
Severity Zones
In 2005, the California Department
of Forestry and Fire Protection (CAL
FIRE) mapped fire threat potential
throughout California based on the
availability of fuel and the likelihood
of an area burning (based on
topography, fire history, and
climate). Fire threat mapped in and
around Diamond Bar is shown in
Figure 7-5. Fire threat in the city was
generally categorized as Moderate,
with areas of higher threat
correlated with open space areas
and slopes. Areas with the greatest
fire threat include the southern
portion of the city surrounding the
Country Estates subdivision and the
open space areas near Sycamore
Canyon and the Summitridge Trails.
The SOI is categorized as Very High
and Extreme threat.
CAL FIRE also maintains mapping
of Fire Hazard Severity Zones (FHSZs)
to aid in State and local planning
for wildland fire protection. In State
Responsibility Areas (SRAs), where
the State of California is financially
responsible for the prevention and
suppression of wildfires, CAL FIRE
identifies Moderate, High, and Very
High FHSZs. In Local Responsibility
Areas (LRAs), where fire protection
is provided by city fire departments,
fire protection districts, counties,
and by CAL FIRE under contract
PUBLIC SAFETY | Diamond Bar General Plan 20407-16
to local government, CAL FIRE
identifies only Very High FHSZs.
Under State law (Government
Code Sections 65302 and 65302.5),
the City of Diamond Bar General
Plan must address the risk of fire
in Very High FHSZs in the LRA
within the City’s jurisdiction, and
the Los Angeles County General
Plan must address the risk of fire
in the surrounding SRA, including
Diamond Bar’s SOI.
As shown in Figure 7-6, Very High
FHSZs are mapped in a number
of locations throughout the city,
including most of the designated
open space areas and much of
the Country Estates subdivision.
In accordance with State law,
policies in this General Plan address
wildland fire hazards in order to
reduce risks both in these zones and
in the city as a whole.
Wildfire History
Figure 7-7 shows perimeters for
historic wildfires in and around
Diamond Bar dating to the 1920s
as mapped by CAL FIRE. As shown,
areas with higher frequency have
included the SOI and surrounding
open spaces outside of the
city. While several overlapping
perimeters are shown in the
northern portion of Diamond Bar, all
of these date to the 1970s or earlier.
Since the 1980s, wildfires have
occurred in locations near Peaceful
Hills Road, Eldertree Drive, Diamond
Knoll Lane, and Wagon Train Lane
in the southern portion of the city;
in and around the SOI; and near
to but outside of the northern city
limits. This data is maintained and
made publicly available through
CAL FIRE’s Fire and Resource
Assessment Program for future
reference.
Wildfire Management Strategies
In recent years, the State of
California has experienced
increasingly severe wildfire seasons
due to factors such as extreme
weather events such as prolonged
drought conditions and high winds,
and the accumulation of fuel. In
2017 and 2018, devastating fires
such as the Camp and Tubbs
fires in northern California and
the Thomas and Woolsey fires in
southern California demonstrated
the profound impact wildland fires
can have on populated areas. As
the State prepares for more such
incidents as the WUI continues to
expand and changes in climate
patterns become more apparent,
wildfire risk management at the
local level will become increasingly
important. Strategies tend to cluster
around two main approaches:
maintaining defensible space
around structures, and ensuring that
structures are resistant to fire.
Defensible space refers to a space
created around development
that is designed and maintained
to reduce the ability of a fire to
spread. Fuel modification is a key
element of creating defensible
space and is intended to disrupt
what would otherwise be a
continuous path that could lead
wildfires to buildings, thus increasing
the chance that the buildings will
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PUBLIC SAFETY
survive. Fuel modification strategies
include plant selection based on
moisture content, resin, and the
production of detritus, and the
proper arrangement of plants
in relation to structures. The Los
Angeles County Fire Department
(LACFD) Fuel Modification Unit is
responsible for the approval of
fuel modification plans for new
structures located in the County’s
FHSZs, including in the Planning
Area. State law requires there to be
at least 100 feet of defensible space
around buildings.
Designing wildfire-resistant
structures means constructing
buildings so that they have less
chance of catching fire from
burning embers. Strategies include
limiting the use of flammable
materials on building exteriors,
protecting vents and chimneys
from embers, protecting windows
from breakage under extreme
heat, and screening gutters to
reduce accumulation of flammable
debris. The California Building Code
includes standards that address fire
risks to structures in the WUI.
PEAKLOAD WATER SUPPLY REQUIREMENT
Diamond Bar engineering standards
require a minimum flow of water
for fire protection in accordance
with LACFD, California Fire Code,
and Insurance Services Office (ISO)
standards.
FIRE ACCESS STANDARDS
Fire access is regulated by the
adopted and amended California
Fire Code and LACFD standards.
The current Fire Code establishes a
minimum distance for all portions
of a building from serviceable fire
access roads. The LACFD establishes
a minimum centerline turning radius
to accommodate fire trucks and
building standards.
PUBLIC SAFETY | Diamond Bar General Plan 20407-18
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COPLEYDRBRIDGEGATEDRVALLEYVISTADRROCKRIVERRDFire Threat Level (Cal Fire)
Extreme Threat
Very High Threat
High Threat
Moderate Threat
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Highways
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City of Diamond Bar
Sphere of Influence
County Boundary
0 0.75 1.50.375
MILES
Source: Fire Threat, Fire and Resources Assessment Program (FRAP), Cal Fire 2005;
Los Angeles County GIS Data Portal, 2016; Dyett & Bhatia, 2019Rive rsideMetrolinkLineFigure 7-5: Fire Threat City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-5 Fire Threat
Diamond Bar General Plan 2040 | PUBLIC SAFETY 7-19
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Highways
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City of Diamond Bar
Sphere of Influence
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0 0.7 1.40.35
MILES
Source: California Department of Forestry and Fire Protection
(CAL FIRE), 2007 & 2009; Los Angeles County GIS Data Portal,
2016; Dyett & Bhatia, 2019 RiversideMetrolinkLineFigure 7-6: Fire Hazard Severity Zones City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-6 Fire Hazard Severity Zones
PUBLIC SAFETY | Diamond Bar General Plan 20407-20
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Year of Occurance
2000 - 2017
1980 - 1999
1960 - 1979
1940 - 1959
1920 - 1939
Highways
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City of Diamond Bar
Sphere of Influence
County Boundary
0 0.5 10.25
MILES
Source: California Department of Forestry and Fire Protection
(CAL FIRE), 2019; City of Diamond Bar, 2019; Dyett & Bhatia, 2019RiversideMetrolinkLineFigure 7-7: Wildfire Perimeters 1928-2019 City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-7 Wildfire Perimeters 1928 – 2019
Diamond Bar General Plan 2040 | PUBLIC SAFETY
7.0
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GOALS & POLICIES
FIRE HAZARDS
GOALS
PS-G-3 Partner with the Los Angeles County Fire
Department and affiliated agencies to
implement hazard mitigation plans and
community education efforts aimed
at preventing the potential for loss of
life, physical injury, property damage,
public health hazards, and nuisances
from wildland and urban fires.
POLICIES
General
PS-P-14 Educate the public about fire hazards and
fire prevention. Work with the County of
Los Angeles Fire Department and CAL FIRE
to disseminate information on fire weather
watches and fire risks and encourage all
Diamond Bar residents to engage in risk
reduction and fire preparedness activities.
The Los Angeles County Fire Department
maintains information on family
fire preparedness plans and
risk reduction measures such as
vegetation management.
PS-P-15 Ensure adherence to applicable Fire and
Building Codes, including standards
for minimum road widths, access and
clearance for emergency vehicles, and
the identification of all roads, streets,
and major public buildings in a manner
that is clearly visible to fire protection
and other emergency vehicles.
PUBLIC SAFETY | Diamond Bar General Plan 20407-22
PS-P-16 For privately-owned property within areas
designated for development that are
subject to high wildfire risk, condition
approval of development upon
the implementation of measures to
reduce risks associated with that
development, including, but not
limited to, fuel modification plans
and Fire Code requirements in effect
at the time of project approval.
PS-P-17 Protect and promote native oak woodlands
that border residential areas as fire buffers.
PS-P-18 Work cooperatively with the County of Los
Angeles Fire Department, CAL FIRE,
and fire protection agencies of
neighboring jurisdictions to address
regional wildfire threats.
Fire Hazard Severity Zones and State Responsibility
Areas
PS-P-19 Maintain and update the City’s High Fire
Hazard Severity Zones map consistent
with changes in designation by CAL
FIRE to ensure that the County of Los
Angeles Fire Department is protecting
the community from wildland-urban fires
as future development takes place.
PS-P-20 Prior to permit approval, ensure that all new
development located in a Very High
Fire Hazard Severity Zone or a State
Responsibility Area (SRA) is served by
adequate infrastructure, including
safe access for emergency response
vehicles, visible street signs, and
water supplies for fire suppression.
PS-P-21 Collaborate with the County of Los Angeles
Fire Department to ensure that properties
in and adjacent to High or Very High
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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GOALS & POLICIES
Fire Hazard Severity Zones as indicated
in Figure 7-6 are adequately protected
from wildland fire hazards in a manner
that minimizes the destruction of
natural vegetation and ecosystems
through inspection and enforcement.
Update Figure 7-6 as new information
becomes available from CAL FIRE.
PS-P-22 Support the County of Los Angeles Fire
Department’s Provision of weed abatement
and brush thinning and removal services
in High and Very High Fire Hazard Severity
Areas in order to curb potential fire hazards.
PS-P-23 Where development is proposed within High
or Very High Fire Hazard Severity Zones,
ensure that the County of Los Angeles Fire
Department has the opportunity to review
the proposal in terms of its vulnerability
to fire hazards and its potential as a
source of fire, including fuel modification
plan review for new development or
additions that are equal or greater than 50
percent of the existing square footage.
PUBLIC SAFETY | Diamond Bar General Plan 20407-24
7.5 HAZARDOUS MATERIALS AND OPERATIONS
Hazardous materials, as defined by
the California Code of Regulations
(CCR), are substances with certain
physical properties that could
pose a substantial present or future
hazard to human health or the
environment when improperly
handled, disposed, or otherwise
managed. This refers to a variety
of injurious substances, including
pesticides, herbicides, toxic metals
and chemicals, liquefied natural
gas, explosives, volatile chemicals,
and radioactive materials.
Hazardous materials are commonly
found throughout the Planning
Area in households and businesses.
Typical residential and commercial
substances include motor oil,
paint, cleaners and solvents,
gasoline, refrigerants, and lawn and
gardening chemicals.
Sites where hazardous chemical
compounds have been released
into the environment can pose
threats to health and ecological
systems. Historic or current activities,
most often associated with industrial
or commercial uses (including
gas stations, car washes, etc.),
may result in the release, leak, or
disposal of toxic substances on or
below the ground surface, where
they can then contaminate soil
and ground water. Disturbance
of the ground through grading or
excavation can result in exposure
of these chemicals to the public.
Improper handling of contaminated
sites may result in further exposure
via airborne dust, surface water
runoff, or vapors.
The California Department of Toxic
Substances Control (DTSC) and State
Water Resources Control Board
(SWRCB) track and identify sites with
known or potential contamination
and sites that may impact
groundwater in accordance with
Section 65962.5 of the California
Public Resources Code (PRC). The
list produced in accordance with
this code is also known as the
Cortese List.
• EnviroStor. The DTSC EnviroStor
hazardous waste facility
and cleanup sites database
identifies sites that have known
contamination or potentially
Diamond Bar General Plan 2040 | PUBLIC SAFETY
7.0
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PUBLIC SAFETY
contaminated sites requiring
further investigation, and
facilities permitted to treat, store,
or dispose of hazardous waste.
The EnviroStor database includes
lists of the following site types:
federal Superfund sites; State
Response, including military
facilities and State Superfund;
voluntary cleanup; and school
sites.
• GeoTracker. The SWRCB
GeoTracker database tracks
sites that impact groundwater
or have the potential to impact
groundwater. It includes sites
that require groundwater
cleanup such as Leaking
Underground Storage Tanks
(LUSTs), Department of Defense,
and Site Cleanup Program sites;
as well as permitted facilities
that could impact groundwater
such as operating Underground
Storage Tanks (USTs), irrigated
lands, oil and gas production
sites, and land disposal sites.
Sites in the Planning Area listed by
either SWRCB or DTSC as of May
2019 are shown on Figure 7-8. In
general, contaminated sites are
largely found along the city’s major
local roadways (e.g., Diamond Bar
Boulevard, Grand Avenue, Golden
Springs Drive). The majority of listed
sites listed by the SWRCB are LUST
cleanup sites, most of which are
automobile-related uses such as
gas stations. As of 2019, most of
those cases had been closed. Also
present in the Planning Area are
a number of sites enrolled in the
Regional Water Quality Control
Board (RWQCB) Waste Discharge
Requirements (WDR) program to
regulate discharges into receiving
waters. The program typically
regulates discharges of domestic
or municipal wastewater, food
processing related wastewater,
and industrial wastewater. As of
2019, there were 17 permitted
underground storage tanks, one
open LUST Cleanup Program case,
one open SWRCB Cleanup Program
case, nine WDR program sites, one
open DTSC Voluntary Cleanup
program case, and one open DTSC
evaluation within the Planning Area.
PUBLIC SAFETY | Diamond Bar General Plan 20407-26
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Source: GeoTracker, State Water Resources Control Board
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Control (DTSC), 2019; City of Diamond Bar, 2019Riv ersideMetrolinkLineFigure 7-8: Hazardous Materials and Sites City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-8 Hazardous Materials and Sites
Diamond Bar General Plan 2040 | PUBLIC SAFETY
7.0
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GOALS & POLICIES
HAZARDOUS MATERIALS AND OPERATIONS
GOALS
PS-G-4 Support the enforcement of applicable
local, County, State, and federal regulations
pertaining to the manufacture, use,
transportation, storage and disposal of
hazardous materials and wastes in the
City with the primary focus on preventing
injury, loss of life, and damage to property
resulting from the potential detrimental
effects (short- and long-term) associated
with the release of such substances.
POLICIES
PS-P-24 Work with the County of Los Angeles Fire
Department to maintain and enforce State
regulations that require proper storage
and disposal of hazardous materials
to reduce the likelihood of leakage,
explosions, or fire, and to properly contain
potential spills from leaving the site.
PS-P-25 On sites with known contamination of soil
and groundwater, work with State and
local agencies to continue to identify
and compel cleanup of such sites to
ensure that construction workers, future
occupants, the public, and the environment
are adequately protected from hazards
associated with contamination.
The City may reference the State Water
Resources Control Board’s Geotracker
database and the California
Department of Toxic Substances
Control’s Envirostor database to
identify potentially hazardous sites.
Figure 7-7 shows sites identified
through these databases in 2019.
PUBLIC SAFETY | Diamond Bar General Plan 20407-28
PS-P-26 Prohibit (or oppose when outside of the
City’s jurisdiction) the development
of projects that would reasonably be
anticipated to emit hazardous air emissions
or handle extremely hazardous substances
within a quarter-mile of a school.
PS-P-27 Work with the County of Los Angeles Fire
Department and other State and federal
agencies to ensure adequate emergency
response for hazardous materials incidents.
PS-P-28 Promote public awareness and
participation in household hazardous
waste management, solid waste,
and recycling programs.
For additional policies related to
household hazardous waste
management, solid waste, and recycling
programs, see Chapter 8: Community
Health and Sustainability Element.
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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PUBLIC SAFETY
7.6 PUBLIC SAFETY SERVICES
LAW ENFORCEMENT
Law enforcement in the Planning
Area are provided by the
Los Angeles County Sheriff’s
Department (LASD). The Walnut/
Diamond Bar Station, located
at 21695 East Valley Boulevard
in Walnut (Figure 7-9), services
Diamond Bar, Walnut and the
unincorporated area of Rowland
Heights. In the case of emergency,
the San Dimas and Industry
Stations can provide additional
assistance. The LASD also provides
general-service law enforcement
to unincorporated areas of Los
Angeles County, including areas
south of Diamond Bar’s city limits
that are within its SOI.
As of 2019, the LASD’s contract with
Diamond Bar includes the purchase
of a full-time equivalent of 22.5
deputies, or nearly four deputies
per 10,000 residents. Moreoever,
Additional resources that can
deployed to Diamond Bar from
LASD’s 22 other stations and four
Bureaus (Transit Service Bureau,
Parks Bureau, County Services
Bureau and Community Colleges
Bureau). , According to the Sheriff’s
Department, the major obstacles to
meeting response time standards
are traffic during peak rush hour,
and traffic in and around the
schools during the beginning and
ending of business hours.
CRIME PREVENTION THROUGH
ENVIRONMENTAL DESIGN
In addition to Sheriff’s Department
services, additional preventative
measures can reduce crime rates and
the sense of danger in an area. Crime
Prevention Through Environmental
Design (CPTED) is a multi-disciplinary
approach to deterring criminal
behavior through environmental
design. CPTED principles include
natural surveillance or “eyes on the
street,” clear delineation and access to public and private spaces,
and continued upkeep and maintenance of spaces. Cities often
consider crime prevention through environmental design principles in
the location and design of new development in order to complement
law enforcement services and contribute to public safety.
PUBLIC SAFETY | Diamond Bar General Plan 20407-30
FIRE SERVICE
Fire protection and emergency
medical services are provided
by the Los Angeles County Fire
Department (LACFD), which
operates three stations within
Diamond Bar city limits, as shown
in Figure 7-9. In addition to fire
protection service and emergency
medical services, the LACFD
provides personnel to serve on
specialized rescue teams, offer
special training programs, and
inspect businesses for fire safety.
The LACFD follows national
guidelines that require a five-minute
response time for first-arriving fire
and EMS units and eight minutes for
paramedic units in urban areas, as
well as an eight-minute response
time for first-arriving fire and EMS
units and 12 minutes for paramedic
units in suburban areas. In 2015,
the average response time for fire
and emergency calls in the City
of Diamond Bar was 5:38 minutes,
slightly above the target response
time.
Diamond Bar General Plan 2040 | PUBLIC SAFETY 7-31
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City of Diamond Bar
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Figure 7-9: Public Safety Facilities C i t y o f D i a m o n d B a r
GENERAL PLAN UPDATEFigure 7-9 Public Safety Facilities
PUBLIC SAFETY | Diamond Bar General Plan 20407-32
SHERIFF, FIRE, AND EMERGENCY SERVICES
See Chapter 4: Circulation Element for additional
policies regarding traffic management.
GOALS
PS-G-5 Maintain safety services that are responsive
to citizens’ needs to ensure a safe
and secure environment for people
and property in the community.
PS-G-6 Support community-based policing
partnerships to enhance public awareness
of crime prevention and strengthen the
relationship between the Los Angeles
County Sheriff’s Department and
neighborhoods throughout the city.
PS-G-7 Provide effective emergency preparedness
and response programs.
POLICIES
PS-P-29 Coordinate with the Los Angeles County
Sheriff’s Department for review of
applications for new development
and for the intensification of existing
development, ensuring that review is
consistent with Crime Prevention Through
Environmental Design (CPTED) principles.
PS-P-30 Continue to promote the establishment of
neighborhood watch and business watch
programs to encourage community
participation in the patrol of neighborhoods.
PS-P-31 Continue to utilize the contract model of
government with Los Angeles County Fire
and Sheriff’s Departments and provide
facilities, staffing, and equipment to
attain the shortest possible response times
as set forth by the adopted standards
of those public safety organizations.
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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GOALS & POLICIES
PS-P-32 Support the achievement of police and fire
response times through the
implementation of traffic management
measures that mitigate congestion
during peak rush hour and during
school drop-off and pick-up times.
PS-P-33 Monitor fire-flow capability throughout the
Planning Area and improve water
availability and redundancy for any
locations that have flows considered
inadequate for fire protection.
Continue to work with various water
purveyors to maintain adequate
water supply and require on-site water
storage for areas where municipal
water service is not available.
PS-P-34 Coordinate with the County of Los Angeles
Fire Department to review new
development applications for consistency
with applicable Fire Codes.
PS-P-35 Work cooperatively with the Los Angeles
County Fire Department, CAL FIRE, and
fire protection agencies of neighboring
jurisdictions to ensure that all portions of the
Planning Area are served and accessible
within an effective response time.
PS-P-36 Work with the Los Angeles County Sheriff’s
Department and County of Los
Angeles Fire Department to ensure
that the cost of providing new staffing,
facilities, and equipment, including
paramedic services, to support new
development is assessed against the
developments creating that need.
PS-P-37 Maintain area-wide mutual aid agreements
and communication links with
adjacent governmental authorities
and other participating jurisdictions.
PUBLIC SAFETY | Diamond Bar General Plan 20407-34
7.7 EMERGENCY AND DISASTER MANAGEMENT
Due to the prevalence of
unpredictable and unavoidable
hazards in and near the Planning
Area, the City must plan to address
the safety of residents in times of
disaster. The City of Diamond Bar
strives to keep its citizens informed
and prepared for any emergency.
Being prepared can save lives,
protect property and minimize
losses to businesses.
LOCAL HAZARD MITIGATION AND
EMERGENCY OPERATIONS PLANNING
The purpose of emergency
preparedness is to protect the
health, safety and welfare
of the general public during
and after natural, man-made
(technological), or attack-related
emergencies. To handle such
events effectively requires the
coordination of a number of
public and private agencies as
well as the public safety agencies
such as the Diamond Bar Public
Works Department, the Los
Angeles County Fire and Sheriff’s
departments, and State agencies
including the California Emergency
Management Agency (CEMA)
and the California Highway Patrol
(CHP). The City of Diamond Bar
recognizes the importance of
emergency preparedness through
the implementation of the Diamond
Bar Emergency Operations plan
and through collaboration on the
implementation of the County of
Los Angeles All-Hazard Mitigation
Plan. These plans are based on
the functions and principles of the
Standard Emergency Management
System (SEMS), which follows the
FIRESCOPE Incident Command
System (ICS) identifying how the City
fits into the overall SEMS structure.
The City of Diamond Bar also
works with the National Incident
Management System (NIMS), which
provides a consistent nationwide
framework to enable government,
nongovernmental organizations,
and the private sector to prevent,
mitigate, and recover from
incidents.
The California Emergency Services
Act requires the City to manage
and coordinate the overall
emergency and recovery activities
within its jurisdictional boundaries.
Under SEMS, the City is responsible
at two levels, the field response
and local government levels. At
the field response level, the City
and all other agencies use ICS to
aid in a standardized emergency
response. At the local government
level, a designated Emergency
Operations Center (EOC) is used as
the central location for gathering
and disseminating information
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PUBLIC SAFETY
and coordinating all jurisdictional
emergency operations within the
area. During disasters, the City
of Diamond Bar is required to
coordinate emergency operations
with the County of Los Angeles
Operational Area and, in some
instances, other local governments.
Local agencies are a part of a
broader Emergency Management
Systems, overseen by the State
of California’s Southern Region
Emergency Operations Center.
The State of California Multi-Hazard
Mitigation Plan, also known as the
State Hazard Mitigation Plan (SHMP),
was approved by FEMA in 2013. The
SHMP outlines present and planned
activities to address natural hazards.
The adoption of the SHMP qualifies
the State of California for federal
funds in the event of a disaster.
Locally, the County of Los Angeles
adopted an All-Hazard Mitigation
Plan in 2014. The plan has been
approved by California Governor’s
Office of Emergency Services (Cal
OES) and by FEMA. The purpose of
the HMP is to demonstrate the plan
for reducing and/or eliminating risk
in the County. The HMP assesses
risks associated with flooding,
earthquake, wildfire, hazardous
material, and drought hazards, and
identifies mitigation strategies to
reduce the risk.
DISASTER RESPONSE TRAINING
The City of Diamond Bar conducts
frequent staff training so that City
employees are equipped to conduct
the necessary decision-making and
coordination efforts in the event of
an emergency or disaster. The City
also relies on local disaster volunteer
programs, including the following:
• Community Emergency
Response Team (CERT). The
County of Los Angeles provides
emergency preparedness
information and disaster training
for use by individuals in their
own neighborhoods in times
of an emergency, as well as
continuing training for Affiliated
CERT volunteers to assist the
City before, during, and after a
disaster or emergency.
• Los Angeles County Sheriff’s
Department Volunteer on Patrol
Program. The County of Los
Angeles Volunteer program offers
volunteers an opportunity to be
involved with nearly every aspect
of a station, including search and
rescue, clerical duties, and youth
volunteer opportunities.
• FEMA Independent Study
Program. The Emergency
Management Institute (EMI) of the
Federal Emergency Management
Agency (FEMA) offers self-paced
courses designed for people who
have emergency management
responsibilities and the general
public.
PUBLIC SAFETY | Diamond Bar General Plan 20407-36
EMERGENCY AND DISASTER MANAGEMENT
GOALS
PS-G-8 Use the Local Hazard Mitigation Plan and
Emergency Operations Plan to address
mitigation and response for local hazards,
including seismic hazards, flood hazards,
fire hazards, hazardous materials incidents,
and hazardous sites, and to plan for the
protection of critical facilities (i.e., schools,
hospitals), disaster and emergency
response preparedness and recovery,
evacuation routes, peak load water
supply requirements, and minimum road
width and clearance around structures.
PS-G-9 Conduct emergency and disaster
management planning in a collaborative
manner with State and local agencies
and neighboring jurisdictions, while
striving for self-sufficiency in City-
level emergency response.
POLICIES
PS-P-38 Maintain, review, and update Diamond
Bar’s Local Hazard Mitigation Plan as
needed to take into account new hazard
conditions in the Planning Area and new
emergency management techniques.
PS-P-39 Adopt, implement and update as necessary
the Local Hazard Mitigation Plan to
develop strategies to address changing
risks from flood, drought, fire, landslides,
seismic activity, hazardous materials,
and other potential hazards, including
strategies related to monitoring,
emergency preparedness, development
policies, conservation, vulnerable
populations, and community resilience.
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GOALS & POLICIES
PS-P-40 Continue to coordinate the City’s
emergency preparedness and response
plans and operations with the State
Office of Emergency Management,
Los Angeles County, schools, and
other neighboring jurisdictions.
PS-P-41 Maintain and expand as necessary
community emergency preparedness
resources including personnel, equipment,
material, specialized medical and other
training, and auxiliary communications.
PS-P-42 Continue to disseminate public information
and alerts regarding the nature and
extent of possible natural and man-
made hazards, resources identifying
measures residents and businesses can
take to prepare for and minimize damage
resulting from these hazards, citywide
response plans, and evacuation routes.
PS-P-43 Require all City staff to be adequately
trained to respond to emergency
situations, and conduct regular
emergency preparedness drills with local
organizations including the Los Angeles
County fire and Sheriff’s departments.
PS-P-44 Leverage pre- and post-disaster assistance
programs to support resilient planning,
mitigation, and reconstruction strategies
that consider future climate conditions,
such as the California Governor’s
Office of Emergency Services’
Hazard Mitigation Grant Program and
California Disaster Assistance Act.
PUBLIC SAFETY | Diamond Bar General Plan 20407-38
7.8 NOISE
Noise is generally defined as
unwanted sound and can consist
of any sound that may produce
physiological or psychological
damage and/or interfere with
communication, work, rest,
recreation, and sleep. The
classification of sound as noise is
subjective and relies heavily on the
quality and context of the sound.
NOISE MEASUREMENT
The following noise measurement
scales are used to describe noise in
a particular location:
• Frequency. Frequency is the
composition or spectrum of the
sound. Frequency is a measure
of the pressure fluctuations per
second of a sound wave.
• Level. The decibel (dB) system
of measuring sound gives a
rough connection between the
physical intensity of sound and
its perceived loudness to the
human ear. A 10 dB increase
in sound level is perceived
by the human ear as only a
doubling of the loudness of the
sound. Decibel measurement
may also be “A-weighted” to
de-emphasize the very low and
very high frequency components
of the sound in a manner similar
to the frequency response of
the human ear in a manner that
correlates well with subjective
reactions to noise. Ambient
sounds generally range from 30
A-weighted decibels (dBA) (very
quiet) to 100 dBA (very loud).
• Variation. Variation is the sound
level over time. Predominant
rating scales for human
communities in the State of
California are Equivalent Noise
Level (Leq) and the Community
Noise Equivalent Level (CNEL)
or the day-night average level
(Ldn) based on A-weighted
decibels. CNEL is the time-
varying noise over a 24-hour
period, with a 5-dBA weighting
factor applied to the hourly Leq
for noises occurring from 7:00
p.m. to 10:00 p.m. (defined as
relaxation hours) and a 10 dBA
weighting factor applied to
noise occurring from 10:00 p.m.
to 7:00 a.m. (defined as sleeping
hours). Ldn is similar to the CNEL
scale but without the adjustment
for events occurring during the
evening hours. CNEL and Ldn are
within 1 dBA of each other and
are normally interchangeable.
The noise adjustments are
added to the noise events
occurring during the more
sensitive hours.
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PUBLIC SAFETY
NOISE IMPACTS
Noise impacts can be described in
three categories. The first includes
audible impacts, which refer to
increases in noise levels noticeable
to humans. Audible increases in
noise levels generally refer to a
change of 3 dB or greater, since
this level has been found to be
barely perceptible in exterior
environments. The second category,
potentially audible, refers to a
change in the noise level between
1 and 3 dB. This range of noise levels
has been found to be noticeable
only in laboratory environments. The
last category includes changes in
noise level of less than 1 dB, which
are inaudible to the human ear.
Only audible changes in existing
ambient or background noise
levels are considered potentially
significant.
Physiological Effects of Noise
Physical damage to human hearing
begins at prolonged exposure to
noise levels higher than 85 dBA.
Exposure to high noise levels affects
the entire system, with prolonged
noise exposure in excess of 75
dBA increasing body tensions and
thereby affecting blood pressure
and functions of the heart and the
nervous system. In comparison,
extended periods of noise exposure
above 90 dBA would result in
permanent cell damage. When
the noise level reaches 120 dBA,
a tickling sensation occurs in the
human ear, even with short-term
exposure. This level of noise is called
the threshold of feeling. As the
sound reaches 140 dBA, the tickling
sensation is replaced by the feeling
of pain in the ear. This is called the
threshold of pain. A sound level of
160 to 165 dBA will potentially result
in dizziness or loss of equilibrium.
The ambient or background
noise problem is widespread and
generally more concentrated in
urban areas than in outlying, less-
developed areas. Figure 7-10 shows
common sound levels and their
noise sources.
Noise-Sensitive Receptors
Noise-sensitive receptors are land
uses associated with indoor and/
or outdoor activities where the
presence of unwanted sound
could adversely affect the use of
the land. Examples may include
residential areas, senior and child
care facilities, schools, hospitals,
and religious facilities. Special Status
species and their habitats are also
considered noise-sensitive. Noise-
sensitive receptors within the city
include single- and multi-family
residential housing, schools, parks,
libraries, hospitals, churches and
other religious facilities, wildlife
habitat, and open space.
SOURCES OF NOISE
Diamond Bar is an urbanized
area with pockets of open space.
The major sources of noise within
the city include typical urban
noise generators such as vehicle
traffic along roadways, industrial
and commercial processes, and
residential noises such as people
talking, sports events in parks, and
vocalizations from domesticated
animals.
PUBLIC SAFETY | Diamond Bar General Plan 20407-40
Figure 7-10 Typical Noise Levels in the Environment
Common Noise
Source
Noise Level (dBA)Effect
Thunderclap (near)
Symphony Orchestra
Powersaw (chainsaw)
Stereo (over 100 watts)
Garbage Truck /
Cement Mixer
Moto rcycle
Average City Traffic
Garbage Disposal
Vacuum Cleaner, Hair Dryer
Normal Conversation
Quiet Office
Refrigerator
Whisper
Rustling Leaves
Normal Breathing
Uncomfortably
Loud
120 dBA
110 dBA
100dBA
90dBA
80 dBA
70 dBA
60 dBA
50 dBA
40 dBA
30dBA
20 dBA
10 dBA
Threshold of pain begins ~ 125 dB
Regular exposure to sound over
100 dB of more than one-minute
risks permanent hearing loss
No more than 15 minutes
of unprotected expsure
recommended for sounds between 90-100 dB
Very annoying (88dB)
Where hearing damage begins
(85 dB, 8 hrs.)
Instrusive; interderes with telephone conversation
Comfortable hearing levels (< 60
dB)
Very quiet (30 dB)
Just audible (20 dB)
Very Loud
Moderately
Loud
Quiet
Very
Quiet
Source: U.S. Department of Health and Human Services, National Institute on Deafness and Other Communication Disorders 2010; American Medical
Association and the Canadian Hearing Society of Ontario; and National Institute on Deafness and Other Communication Disorders, National Institutes
of Health, 1990.
Diamond Bar General Plan 2040 | PUBLIC SAFETY
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PUBLIC SAFETY
Traffic
Vehicular traffic is the predominant
noise source within Diamond
Bar. The level of vehicular traffic
noise varies with many factors,
including traffic volume, vehicle mix
(including percentage of trucks),
traffic speed, and distance from
the roadway. Major traffic noise
sources in Diamond Bar include
freeways (SR-57 and SR-60) and
arterial roadways such as Brea
Canyon Road, Diamond Bar
Boulevard, Golden Springs Drive,
Grand Avenue, and Pathfinder
Road. Figure 7-11 shows the contours
of existing noise levels (2019) along
roadways in the Planning Area, and
Figure 7-12 shows projected noise
level contours at buildout of General
Plan land uses in 2040.
Railway
The noise impacts associated with
rail activities depend on a number
of factors, including the type of
train, the length of train, the use of a
horn, the physical track conditions,
the geometry and intervening
structures between the rail line and
its receptor, the number of trains
operating, and the speed of the
train. While no rail lines pass through
Diamond Bar, the Union Pacific rail
line runs adjacent to the western
portions of the city, including a
Metrolink stop at Diamond Bar’s
border with the City of Industry.
Noise impacts from the railway
will need to be considered as the
Transit-Oriented Mixed-Use area is
developed, particularly with regards
to sensitive receptors.
One potential railway noise
mitigation measure that the
City could consider would be to
coordinate with relevant agencies
and private entities to implement
a railroad quiet zone. A quiet zone
is an exemption granted by the
Federal Railroad Administration
(FRA) to the rule requiring trains
to sound their horns when
approaching public highway-
rail grade crossings, such as the
railroad crossing at South Lemon
Avenue. Given that trains sound
their horns upon the approach to a
crossing for safety reasons, to alert
vehicles and people that the train is
approaching, grade crossings within
quiet zones are typically required to
include additional safety measures
such as upgraded warning devices.
Stationary Noise Sources
Commercial-industrial and light-
industrial land uses in the city have
the potential to generate high noise
levels and impact surrounding land
uses with their equipment operation.
Noise sources from these land
uses include: air conditioning or
refrigeration units, power tools, lawn
equipment, generators, and other
powered mechanical equipment.
Other Noise Sources
Other sources of noise can include
construction and the use of portable
or small-scale pieces of equipment.
Construction can be a substantial,
though short-term, source of noise,
and is most disruptive when it takes
place near sensitive uses or during
night or early morning hours. Power
equipment, such as leaf blowers
and drills, can produce high noise
levels at the location of work. Other
amplified sounds, such as audio
equipment at either a sanctioned
event or residential property, can
also create noise exposure.
PUBLIC SAFETY | Diamond Bar General Plan 20407-42
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CO PLEYDRBRIDGEGA TED RVALLEYVISTADRROCKRIVERRDExisting Noise Levels
75 dB Contour
70 dB Contour
65 dB Contour
60 dB Contour
Highways
Ramps
Major Roads
Local Roads
Railroads
Water Features
City of Diamond Bar
Sphere of Influence
County Boundary
0 0.7 1.40.35
MILES
Source: ESA PCR, 2016; City of Diamond Bar 2019;
Dyett & Bhatia, 2019 RiversideMetrolinkLineFigure 7-11: Existing Noise Contours (2016)City of Diamond Bar
GENERAL PLAN UPDATEFigure 7-11 E xisting Noise Contours (2016)
Diamond Bar General Plan 2040 | PUBLIC SAFETY 7-43
Existing Noise Levels
70 dB Contour
65 dB Contour
60 dB Contour
Highways
Ramps
Major Roads
Local Roads
Railroads
Water Features
City of Diamond Bar
Sphere of Inuence
County Boundary
0 0.7 1.40.35
MILES
Source: ESA, 2016; City of Diamond Bar 2019;
Dyett & Bhatia, 2019 Riverside Metrolink LineFigure 7-12: Future Noise Contours (2040)City of Diamond Bar
GENERAL PLAN UPDATE
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PUBLIC SAFETY | Diamond Bar General Plan 20407-44
Table 7-1: Community Noise Compatibility Matrix
Land Use Categories
Maximum Exterior Community Noise Equivalent Level (CNEL)
or Day-Night Level (Ldn), dB1
Maximum
Interior
CNEL
55 60 65 70 75 80
Rural, Single-Family, Multiple-
Family Residential
40
School Classrooms 40
School Playgrounds
Libraries 40
Hospitals, Convalescent
Facilities Living Areas
45
Hospitals, Convalescent
Facilities Sleeping Areas
35
Recreation: Quiet, Passive
Areas
40
Recreation: Noisy, Active
Areas
Commercial and Industrial
Office Areas 45
Normally Acceptable:Specified land use is satisfactory, based upon the assumption that any
buildings involved are of normal conventional construction, without any special noise
insulation requirements. Outdoor areas are suitable for normal outdoor activities for this
land use.
Conditionally Acceptable: New construction or development should be undertaken only
after a detailed analysis of the noise reduction requirements is made and needed noise
insulation features included in the design. Conventional construction, but with closed
windows and fresh air supply systems or air-conditioning, will normally suffice.
Normally Unacceptable:New construction or development should generally be discouraged.
If new construction or development does proceed, a detailed analysis of the noise reduction
requirements must be made and needed noise insulation features included in the design.
Clearly Unacceptable:New construction or development should generally not be
undertaken.
Nature of the Noise environment where the CNEL or Ldn level is:
•Below 55 dB: relatively quiet suburban or urban areas, no arterial streets within 1 block, no freeways
within ¼ mile.
•55-65 dB: most somewhat noisy urban areas, near but not directly adjacent to high volumes of traffic.
•65-75 dB: very noisy urban areas near arterials, freeways or airports.
•75+ dB: extremely noisy urban areas adjacent to freeways or under airport traffic patterns. Hearing
damage with constant exposure outdoors.
Notes:
1.The Community Noise Equivalent Level (CNEL) and Day-Night Noise Level (Ldn) are measures of the
24-hour noise environment. They represent the constant A-weighted noise level that would be measured
if all the sound energy received over the day was averaged. In order to account for the greater sensitivity
of people to noise at night, the CNEL weighting includes a 5-decibel penalty on noise between 7:00 pm
and 10:00 pm and a 10-decibel penalty on noise between 10:00 pm and 7:00 am of the next day. The Ldn
includes only the 10-decibel weighting for late-night noise events. For practical purposes, the two
measures are equivalent for typical urban noise environments.
Table 7-1: Community Noise Compatibility Matrix
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GOALS & POLICIES
NOISE
GOALS
PS-G-10 Protect public health and welfare by
enforcing the City’s noise ordinance,
and impose mitigation measures
on future development and uses to
prevent significant degradation of
the future acoustic environment.
PS-G-11 The location and design of transportation
facilities, industrial uses, and other potential
noise generators shall not adversely
affect adjacent uses or facilities.
PS-G-12 Support measures to reduce noise emissions
by motor vehicles, aircraft, and trains.
POLICIES
PS-P-45 Use the noise and land use compatibility
matrix (Table 7-1) and Projected Noise
Contours map (Figure 7-12) as criteria
to determine the acceptability of a
given proposed land use, including the
improvement/construction of streets,
railroads, freeways, and highways.
PS-P-46 Locate new noise sensitive uses—including
schools, hospitals, places of worship,
and homes—away from sources
of excessive noise unless proper
mitigation measures are in place.
PUBLIC SAFETY | Diamond Bar General Plan 20407-46
PS-P-47 As feasible, locate land uses to buffer
residential uses from potential
noise generators and site buildings
to serve as noise buffers.
PS-P-48 Maintain interior and exterior noise-related
development standards through the
Diamond Bar Noise Control Ordinance.
PS-P-49 Ensure that detailed site-specific noise
analysis, including the identification of
noise mitigation measures, be prepared
for all development proposals located
where project noise exposure would
be other than normally or conditionally
acceptable as specified in Table 7-1.
With mitigation, development should
meet the allowable exterior and interior
noise exposure standards established
in the Noise Control Ordinance.
PS-P-50 Evaluate the land use compatibility of any
proposed development project prior
to approval to avoid locating loud
developments near noise sensitive
receptors. When walls over six feet in height
are necessary to mitigate noise, a berm/
wall combination with heavy landscaping, a
terraced wall heavily landscaped, or other
similar innovative wall design technique
shall be used to minimize visual impacts.
PS-P-51 Coordinate with the Union Pacific Railroad
and other agencies and private entities to
consider the implementation of a railroad
quiet zone and other methods of reducing
railroad noise impacts on surrounding
noise-sensitive uses along the Union
Pacific Railroad line adjacent to the city.
PS-P-52 Ensure that noise attenuation facilities are
installed as feasible in all noise-sensitive
areas impacted by County, State, or federal
highways through coordination with Caltrans
and the Federal Highway Administration.
A wide range of health
outcomes and risks are
influenced by the social and
physical environments we
inhabit – the places we live,
work, learn and play – as well
as access to opportunities such
as jobs and resources such
as services and recreational
facilities.
COMMUNITY
HEALTH &
SUSTAINABILITY 8.0
COMMUNITY HEALTH & SUSTAINABILITY | Diamond Bar General Plan 20408-2
8.1 INTRODUCTION
Health and wellbeing are shared
goals of all residents of Diamond
Bar, and the City is committed to
promoting the welfare of all its
residents by improving public health
through policies and programs
that contribute to a sustainable
environment, safe and convenient
multi-modal transportation options,
access to healthy food, and a
strong community. Additionally,
the City is focused on building
resiliency to adapt to the impacts
of climate change, which pose an
immediate and growing threat to
the health and welfare of Diamond
Bar residents, and promoting the
reduction of greenhouse gas (GHG)
emissions to reduce potential
impacts. This Chapter addresses
the ways in which the physical
environment can influence the
long-term health and sustainability
of the community, including the
topics of environmental justice,
active lifestyles, social connection,
public health and human services,
and climate change in order to
strengthen the community’s overall
long-term resilience. The Climate
Action Plan (CAP) associated
with the General Plan provides
an in-depth discussion of climate
change impacts, an inventory
of existing and projected GHG
emissions, and additional optional
strategies to complement policies
included in this chapter focused on
reducing GHG emissions, resiliency,
and adaptation.
RELATIONSHIP TO STATE LAW
Government Code Section 65302
requires that general plans include
either an environmental justice
element or related goals, policies,
and objectives integrated into
other elements, that identify any
disadvantaged communities within
the Planning Area, and provide
policies to reduce the unique or
compounded health risks facing
those communities.
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The additional health-related
sections of this chapter are not
required by State law, but address
issues that are important to
Diamond Bar. Government Code
Section 65303 enables the City
to adopt “any other elements or
address any other subjects, which,
in the judgment of the legislative
body, relate to the physical
development of the... city.” Once
adopted, an optional element has
the same force and effect as the
mandatory elements. Accordingly,
zoning, subdivisions, public works,
specific plans, and other actions
that must be consistent with the
general plan must be consistent
with any optional elements. Over
the past decade, optional elements
addressing health, wellness and
sustainability have become more
common.
RELATIONSHIP TO OTHER ELEMENTS
Given that health and sustainability
are influenced by a wide range
of issues related to the physical
environment, this chapter is closely
linked to policies in each of the
other chapters. Chapter 2, Land
Use and Economic Development,
and Chapter 3, Community
Character and Placemaking
outline desired land use patterns
affect health by ensuring that
neighboring uses are compatible
and encourage walkable
development patterns to support
active lifestyles and greenhouse
gas (GHG) emissions reduction.
Chapter 4, Circulation similarly
addresses expanded opportunities
for active transportation. Chapter
5, Resource Conservation discusses
public-health related issues such
as air quality and water quality; air
pollutant emissions are also closely
tied to GHG emissions. Chapter
6, Public Facilities and Services
includes policies related to public
programs and services, including
the provision of parks and schools.
Chapter 7, Public Safety discusses
hazards in the Planning Area,
including those that impact public
health.
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8.2 PUBLIC HEALTH AND ENVIRONMENTAL JUSTICE
PUBLIC HEALTH
Public health encompasses a
variety of health considerations that
address the physical, mental, and
social well-being of a community. A
well-rounded public health system
will consider a wide range of factors
including environmental health,
active lifestyles, social connections,
and access to health and human
services and healthy food.
Environmental Health
On a basic level, ensuring adequate
environmental health means
making sure that a community’s
fundamental environmental health
needs, such as clean water and
clean air, can be safely met, and
that people are not at risk of
exposure to hazardous materials in
their surroundings. As discussed in
Chapter 5, Resource Conservation,
air quality in the Planning Area
is compromised by high levels of
pollutants, the majority of which
are generated by vehicle traffic.
Air contaminants can produce
lung irritation and exacerbate
existing respiratory conditions,
and have been tied to increased
rates of asthma hospitalization
for youth and mortality among
seniors. Air contaminants can also
contribute to risk of lung cancer
and cardiovascular disease.
Vehicle traffic is also the main
source of noise in the Planning
Area, as discussed in Chapter 7,
Public Safety. High levels of noise
can also lead to physiological or
psychological damage and/or
interfere with communication, work,
rest, recreation, and sleep. Just as
maintaining environmental quality
is essential to ecological health in
the area, it is essential to promoting
health among community members.
Active Lifestyle
Active living refers to incorporating
physical activity into one’s daily life.
Examples of active living include
walking to transit to commute
to work and walking or biking to
school or social activities. Daily
physical activity is a crucial aspect
of reducing risk of a host of chronic
diseases. Lack of physical activity
is a risk factor for heart disease,
cancer, stroke, diabetes, and
Alzheimer’s; and a primary risk
factor for obesity. Conversely, active
living is associated with improved
mental health, longer lifespans, and
better quality of life. In addition to
the benefits of active living on an
individual level, increased levels
of physical activity also have the
potential to reduce public health
and medical costs associated with
chronic diseases.
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Certain environments, such as
those where the only commute
option is to drive or where public
facilities and other destinations
are located far from residences,
make it difficult for people to
lead active lives. As is discussed in
Chapter 4, Circulation, vehicular
mode share, or the percentage
of residents who drive to get to
work, is high as a result of the City’s
layout and distribution of land
uses. The ability to reduce reliance
on single-occupant vehicles and
promote active living through the
provision of pedestrian and bicycle
facilities and improvements and
the incorporation of new mixed-
use centers that expand access to
nearby shops, entertainment and
services within walking or cycling
distance from their homes create
opportunities for more active
lifestyles. Policies in Chapter 6,
Public Facilities and Services also
support the provision of parks and
trails where Diamond Bar residents
can go to exercise outdoors.
Social Connections
In addition to the physical
environment, the strength of social
networks and how the community
engages with physical space has
a strong impact on health and
welfare at both the individual
and community-wide level. Social
interactions can contribute to
both physical and mental health,
and strong social networks can
improve the resiliency of residents
in the face of natural disasters and
emergencies.
Diamond Bar has a network of
community facilities designed to
host community programs and
events. The City offers a variety
of recreational, artistic and
educational programs, and special
events that allow the community
to come together. Members of
the community have voiced a
desire for more facilities and
programming that will engage more
youth and seniors, and reinforce
the community’s reputation as
a “small town” where neighbors
know and support each other. As
the population becomes more
ethnically diverse, spaces and
opportunities for the community
to come together to celebrate
cultural differences and shared
values will be increasingly valuable.
In addition, the growing population
of seniors will benefit from activities
and programs that help them
maintain social connections and
networks despite changes in
their ability or mobility. Chapter
6 includes policies that address
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community facilities, and Chapter
3 includes policies that address
increasing gathering spaces and
encouraging public interaction
through good design.
Healthcare and Human Services
Access to health care services is
a crucial determinant of overall
community health given that
medical monitoring, advice, and
care is often essential to preventing
disease and improving health
outcomes. While Diamond Bar does
not have any public health centers
or hospitals within its jurisdictional
boundaries, residents may visit
hospitals in neighboring jurisdictions.
Hospitals such as Pomona Valley
Hospital Medical Center and St.
Jude Hospital/Medical Center in
Fullerton include Diamond Bar
in their primary service areas or
catchment areas. The Diamond
Bar community also has access to
two nearby Los Angeles County-run
public health centers located in
Pomona and Monrovia. These health
centers provide health services
for free or on a sliding scale to
low-income individuals and those
without access to health insurance.
Diamond Bar’s Diamond Ride
program, a subsidized curb-to-
curb cab service program, helps
to support access to health and
human services for persons with
disabilities and those age 60 and
older residing in Diamond Bar.
Healthy Food
An individual’s access to healthy
food options is another significant
determinant of health. The County
of Los Angeles Public Health 2015
survey data indicates that an
overwhelming majority of parents
and guardians in the Pomona
Health District, which comprises
Diamond Bar and neighboring
jurisdictions, rated community
access to fresh fruits and vegetables
as excellent or good. The same
AGING IN PLACE
Aging in Place is a term used to refer to
policies, services and structures related
to the physical and social environment
that allow older people to remain in
their communities and “age actively,” or
continue to participate fully in society
without compromising safety or security.
Communities that support ageing in
place typically feature accessible
pedestrian infrastructure, supportive
housing options that feature design that
allows older people to remain in their
homes longer, and access to key social
services.
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dataset simultaneously reveals,
however, that more than 20 percent
of children in grades 5, 7, and 9
and adults are obese. Many studies
have found associations between
quality of retail food environment
and rates of obesity and diabetes.
For example, when fast food
restaurants are located adjacent
to high schools, it is convenient for
students to choose unhealthy food
options.
Encouraging healthy eating can
include actions such as increasing a
community’s knowledge of healthy
food choices and behaviors, as well
as promoting alternative healthy
food options such as farmer’s
markets, community gardens and
community-supported agriculture
services (CSAs), which have
the added benefit of providing
opportunities for social interaction
and community engagement and
supporting local food producers.
ENVIRONMENTAL JUSTICE
Environmental justice refers to the
fair treatment and meaningful
involvement of all people regardless
of race, color, national origin,
or income with respect to the
development, implementation and
enforcement of environmental
laws, regulations and policies.
While environmental justice has
traditionally focused on pollution
burdens and their relationship to
health, which are discussed in the
context of Diamond Bar below,
the concept of environmental
justice has broadened to include
environmental and social
vulnerabilities that determine health
such as access to services, healthy
food, and opportunities, thus
overlapping with other community
health topics addressed in this
Chapter.
Disadvantaged Communities
Environmental justice is typically
examined in the context of
disadvantaged communities. The
term “disadvantaged community”
(DAC) is defined by the California
Health and Safety Code, Section
39711, and refers to areas
disproportionately affected by
environmental pollution and other
hazards that can lead to negative
public health effects, exposure
to hazards, or environmental
degradation, and socio-economic
vulnerability, determined by
concentrations of people that are
of low income, high unemployment,
low levels of homeownership, high
rent burden, sensitive populations,
or low levels of educational
attainment.
Identifying DACs is the responsibility
of local jurisdictions. SB 1000
specifies several ways for local
jurisdictions to identify DACs,
including the “off-the-shelf” method
of using public maps published
by the California Environmental
Protection Agency (CalEPA),
which is responsible for identifying
disadvantaged communities
pursuant to Health and Safety Code
Section 39711. Each census tract in
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the state is quantitatively evaluated
for environmental pollution and
vulnerability to the pollution.
CalEPA identifies the census tracts
that score in the top 25 percent
in terms of pollution burden and
socioeconomic vulnerability as
“disadvantaged communities.”
As of 2019 no disadvantaged
communities have been identified
by CalEPA in Diamond Bar or its
Sphere of Influence, however
this doesn’t preclude the City of
Diamond Bar from incorporating
the principles of environmental
justice into its planning and policies,
principles that are consistent with
values shared by Diamond Bar
residents such as inclusivity, fairness
and equity and an understanding
that a community is only as resilient
as its most vulnerable populations.
Incorporating these principles into
the City’s planning and policies will
also help to ensure that Diamond
Bar continues to aspire toward
being among the most inclusive
communities to be found. The City
can tackle procedural inequities,
for instance, or inequities that occur
when the planning process is not
conducted in a uniform manner,
by meeting community members
where they are, at times that allow
for broader participation, and by
translating documents or providing
interpretation services to those who
are not comfortable providing input
in English. Providing materials and
outreach opportunities in other
languages is and will continue
to be particularly important in
Diamond Bar, where levels of limited
English speaking, also referred
to as linguistic isolation, are high
according to CalEPA and US Census
Bureau data.
Pollution Burdens in Diamond Bar
The data provided by CalEPA in
terms of pollution burden indicators
is useful in terms of evaluating
environmental health risks in
Diamond Bar. Table 8-1 shows
Planning for Healthy Communities
SB 1000
Implementation Toolkit
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COMMUNITY HEALTH AND SUSTAINABILITY
the percentile rank of select
pollution burden indicators used
by CalEPA for census tracts in
Diamond Bar. The percentile
rank for a given indicator
represents the percentage of
census tracts in all of California
with lower values of that
indicator. For example, the
majority of the census tracts in
the Planning Area are in the 74th
percentile or above for Ozone,
which means that each census
tract has worse Ozone pollution
than 74 percent of census tracts in
California. While the rankings do
not necessarily reflect whether or
not any given indicator is in non-
compliance with existing standards
for safety (for example, a high
ranking for water contamination
does not necessarily indicate that
the water is unsafe to drink by
State standards), they do illustrate
clear geographical disparities in
environmental quality.
Census tracts within the Planning
Area are burdened with particularly
high levels of fine particulate
matter (PM 2.5), diesel particulate
matter (diesel PM), and ozone.
Fine particulate matter can
originate from a variety of sources,
including cars and trucks, industrial
processes, wood burning, or other
activities involving combustion,
and wildfires. Because the particles
are microscopic in size, they can
be inhaled and affect both the
lungs and heart, causing heart
attacks, aggravated asthma,
decreased lung function, and
other complications. Ozone is a
common air pollutant in the region
that is produced in the atmosphere
by chemical reactions between
oxygen-containing compounds and
other air pollutants in the presence
of sunlight. Emissions from industrial
facilities and electric utilities, motor
vehicle exhaust, gasoline vapors,
and chemical solvents are some
of the major sources of these
substances. Breathing ozone can
trigger a variety of health problems,
particularly for children, the elderly,
and people of all ages who have
lung diseases such as asthma.
Drinking water and hazardous waste
are two other pollution burden
indicators where census tracts in
Diamond Bar tend to score high
relative to other census tracts in
California. It is important to note
that both drinking water and
hazardous waste are regulated
by standards at the State level.
These indicators do not, therefore,
necessarily point to major threats to
human health.
Strategies available to the
City to address these pollution
burdens include collaborating
with neighboring jurisdictions and
regional bodies such as the South
Coast Air Quality Management
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Table 8-1: Percentile Ranks for Select Pollution Burden Indicators in
Diamond Bar Disadvantaged Communities
Census Tract Ozone³PM2.5 4 Diesel5 Drinking6 Water Traffic7 Hazardous Waste8
Total Pollution Burden9
403303 74 69 95 28 82 77 83
403304 69 69 79 28 84 19 57
403305 69 34 0 90 38 8 25
403312 78 82 97 54 96 47 93
403316 82 71 0 94 48 49 38
403319 78 96 0 95 49 26 26
403320 78 21 0 41 40 69 18
403321 82 23 0 95 45 50 15
403322 74 90 0 96 48 42 28
403323 74 98 0 94 50 78 31
403324 74 30 0 43 40 13 22
403325 69 34 0 91 38 41 18
408703 65 69 25 52 82 18 56
Notes:
1. The percentile represents a relative score for the indicators, in comparison to all census tracts in California.
2. Percentile values are rounded to the nearest one percent.
3. Based on amount of daily maximum 8-hour ozone concentration.
4. Based on annual mean of fine particulate matter concentrations.
5. Based on County-wide estimates for a July weekday.
6. Based on drinking water contaminant index for selected contaminants. The drinking water contaminant
index is a combination of contaminant data that takes into account the relative concentrations of different
contaminants and whether multiple contaminants are present. The drinking water contaminant index is
not a measure of compliance with drinking water standards and does not indicate whether water is safe to
drink.
7. Based on traffic volumes on road segments within 150 meters of the census tract boundary.
8. Based on the sum of weighted permitted hazardous waste facilities and hazardous waste generators
within each census tract.
9. Based on average of percentiles from all pollution burden indicators.
Source: CalEnviroScreen 3.0, 2018
District (SCAQMD) (see Chapter 5 for
further discussion and policies related
to air quality and water quality);
protecting sensitive populations such
as young people and aging adults
from environmental risks through
appropriate land use planning and
mitigation requirements such as
adherence to SCAQMD’s air quality
buffers as is referenced in Chapter
5; and ensuring that hazardous
waste does not pose a threat to
human health through appropriate
land use and hazardous waste
regulations, as outlined in Chapter
7: Public Safety.
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GOALS & POLICIES
ACTIVE LIFESTYLE
See Chapter 4: Circulation for additional policies
regarding the promotion of multi-modal mobility. See
Chapter 6: Public Facilities and Services for additional
policies regarding the provision of parks and public
facilities.
GOALS
CHS-G-1 Support healthy and active lifestyles for all
members of the community by
integrating opportunities for active
transportation and physical activity
into daily life in Diamond Bar.
CHS-G-2 Achieve more walkable, livable
neighborhoods by expanding the multi-
modal transportation system and creating
a safe, pedestrian-oriented environment.
CHS-G-3 Promote the use of public parks,
recreational and other spaces for
healthy exercise and physical activity.
POLICIES
CHS-P-1 Strive to ensure that all areas of the
community have an equal distribution
of public parks and public recreational
facilities to maximize access.
CHS-P-2 As resources become available and
appropriated through the municipal budget
process, improve signs directing residents
and visitors to public parks and recreational
facilities from all parts of the community.
Integrate parks and recreation signage
with bikeway and pedestrian-oriented
signage systems throughout Diamond Bar.
CHS-P-3 Promote physical activity and active
transportation programs through events
sponsored by the City, particularly the
Parks & Recreation Department.
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CHS-P-4 Remove barriers and improve multi-modal
mobility throughout the City for all
community members by supporting transit,
pedestrian, and bicycle connections
between residential neighborhoods
and major destinations, including parks,
civic facilities, school campuses, other
educational institutions, employment
centers, shopping destinations, parks, and
recreation areas, where appropriate.
CHS-P-5 As opportunities and resource become
available, implement street design
features that facilitate walking and biking
in both new and established areas.
Require a minimum standard of these
features for all new developments.
CHS-P-6 Support efforts to improve the conditions for
youth walking and bicycling in the
areas surrounding schools.
SOCIAL CONNECTION
GOALS
CHS-G-4 Embrace physical, cultural, language, and
social diversity, sensitively integrating
and welcoming newcomers into
the established community.
CHS-G-5 Enhance cultural and generational diversity
and social connections through
opportunities for volunteerism and civic
engagement, public gathering places,
public art, family-friendly activities,
and events that connect residents
to one another, helping them to stay
socially active in the community.
CHS-G-6 Provide safe and welcoming opportunities
for meeting and gathering that encourage
face-to-face interactions between people.
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POLICIES
CHS-P-7 Continue to support and promote citywide
events that integrate families, schools,
and the greater community.
CHS-P-8 Foster greater connectivity between
neighborhoods and uses by reducing
physical barriers and implementing
strategies that improve comfort and
safety, such as improved visibility,
lighting, and walkability.
CHS-P-9 Encourage and provide volunteer
opportunities for residents to
engage and support a wide variety
of events and activities.
CHS-P-10 Promote social engagement and healthy
lifestyles for older adults by continuing
to organize and offer appropriate
cultural, recreational, and assistance
programs, activities, and services.
CHS-P-11 Encourage and facilitate incorporation of
universal lifecycle design principles
(design that promotes the ability to
remain in one's house as one ages) in
new residential development, allowing
community members to stay in their
homes and neighborhoods longer.
CHS-P-12 Encourage public art installations that are
diverse in content, media, and siting
that help to create and reinforce the
uniqueness of Diamond Bar and reflect
an array of cultural influences.
CHS-P-13 Support the provisions of spaces, programs
and facilities across the community to
provide opportunities for artistic and
cultural engagement and expression for all
members of the Diamond Bar community.
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CHS-P-14 Encourage the development of
“destinations”—such as the clusters
of commercial uses that draw
residents from the entire community
into the Neighborhood Mixed Use,
the Transit-Oriented Mixed Use, and
the Town Center focus areas.
CHS-P-15 Encourage the establishment of gathering
areas in new neighborhoods.
CHS-P-16 Create safe public spaces through
implementation of Crime Prevention Through
Environmental Design (CPTED) strategies.
HEALTHCARE AND HUMAN SERVICES
See Chapter 2: Land Use and Economic Development
for additional policies regarding the development of
employment opportunities.
GOALS
CHS-G-7 Promote health equity, including equal
access to health facilities, clinics,
goods, services, and economic and
educational opportunities, helping
to ensure wellbeing for residents of
all ages, abilities, and incomes.
POLICIES
CHS-P-17 Support the managed growth of
complementary health services and
medical facilities in Diamond Bar,
including clinics, hospitals, medical
offices, and medical laboratories. Work
with hospitals, medical practices, and
other health care providers to ensure
widespread access to these services.
CHS-P-18 Publicize existing health programs and assist
residents in connecting with County
and community-based health
services and medical facilities.
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CHS-P-19 Encourage the use of schools as community
and neighborhood centers to provide a
range of services and programs, such as
evening courses related to healthy living,
job-training and retraining programs, and
other services for the community at large.
HEALTHY FOOD
GOALS
CHS-G-8 Promote a healthy, balanced, functional,
and equitable food system for the entire
Diamond Bar community by reducing
barriers and increasing access to
locally-grown fruits and vegetables and
increasing community-wide knowledge
of healthy food choices and behaviors.
POLICIES
CHS-P-20 Continue to support and collaborate with
local non-profit organization (such as
the Greater La Puente Valley Meals on
Wheels) to promote and provide food
delivery to Diamond Bar residents who
have difficulty preparing food or obtaining
meals for themselves due to physical,
mental, financial, or other conditions.
CHS-P-21 Promote healthy food and beverages at
City-sponsored events, programs, and
recreation activities. Ensure that safe,
clean drinking water is available for
the public at all City-owned buildings
where public programs occur.
CHS-P-22 Seek opportunities to partner with regional
Community Supported Agriculture
(CSA) as an alternative source of fresh
and healthy fruits and vegetables for
Diamond Bar residents, particularly those
with limited mobility or income, or those
farthest from existing grocery stores.
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CHS-P-23 Support home gardening efforts by
adopting a Home Gardening and
Urban Agriculture Ordinance or
otherwise ensuring that zoning does not
prevent or restrict the use of residential
properties as vegetable gardens.
CHS-P-24 Explore opportunities as they arise to
incorporate community gardens into
City parks and open space areas, and
encourage the Diamond Bar Community
Garden and other organizations
to facilitate the development,
administration, and operation of additional
community gardens in the City.
PUBLIC HEALTH AND ENVIRONMENTAL JUSTICE
GOALS
CHS-G-9 Promote health equity and environmental
justice in Diamond Bar to ensure
the well-being of residents with the
greatest vulnerability to health risks.
CHS-P-10 As opportunities avail themselves, involve
environmental groups, the business
community, and the general public in
the formulation and implementation
of programs that enhance public
health in the City and the region.
POLICIES
CHS-P-25 Cooperate with the Los Angeles County
Department of Public Health and other
agencies to monitor and maintain data
related to Diamond Bar health outcomes
and risk factors, and use this data to
consider development or expansion of
County and City programs to best serve
and protect the Diamond Bar community.
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GOALS & POLICIES
CHS-P-26 At such time that City staffing resources are
available, monitor and maintain data
from CalEPA related to pollution burdens
and socioeconomic vulnerabilities
in Diamond Bar, and use the data to
consider development or expansion of
programs and investments to reduce the
risks of disadvantaged communities.
CHS-P-27 Recognizing the adverse health impacts
associated with compromised air
quality, ensure the protection of sensitive
receptors from exposure to hazardous
concentrations of air pollutants when
reviewing development proposals.
CHS-P-28 To the extent feasible, manage, enhance,
and improve the City's tree canopy as a
valuable ecological and public health
resource, particularly adjacent to and
within sensitive use areas located in
the Air Quality Management District
(AQMD) 500-foot air quality buffer.
CHS-P-29 Incorporate noise mitigation measures,
which could include buffers, noise
barriers, or natural open space, and
vegetation, between new sensitive
uses such as residential units and
schools, and major noise polluters
such as SR-57 and SR-60, the Metrolink
Riverside rail line, and heavy industry.
CHS-P-30 Support a better informed and civically
engaged community by making information
available both in print and electronic
format, and, to the extent possible,
provide this information in the languages
predominantly spoken in the community.
CHS-P-31 Encourage all segments of the Diamond Bar
community, including residents,
businesses, and organizations, to be
involved in the development, adoption,
and implementation of community
health programs and activities.
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8.3 CLIMATE CHANGE AND GREENHOUSE GASES
Climate change impacts pose
an immediate and growing
threat to California’s economy,
environment and public health.
The effects of climate change in
the San Gabriel Valley include
increased temperatures, reduced
precipitation, flooding, and
reduced water supply. It is thus
important that the Diamond Bar
community build resilience to be
able to adapt to these effects,
and also promote the reduction of
greenhouse gas (GHG) emissions to
mitigate, or reduce their impacts.
CLIMATE CHANGE MITIGATION
In California, about 40 percent of
greenhouse gas emissions come
from the transportation sector. For
example, the proximity between
housing and job centers and the
design of transportation networks
determines the distance needed
to travel between destinations
and the transportation mode
choices available. These factors
directly influence the amount of
greenhouse gas emissions from the
transportation sector. Reducing
vehicle miles traveled will help
Diamond Bar reduce its greenhouse
gas emissions and mitigate potential
impacts of climate change, with
the added benefit of reducing
pollutants that affect public health
issues related to air quality in the
city and broader region.
Climate change mitigation refers
to the actions taken to limit the
magnitude or rate of climate
change and its corresponding
effects, and focuses primarily on
the reduction of GHG emissions.
Given the relationship between
transportation and greenhouse
gas emissions in California
and the dominance of single
occupant vehicles in Diamond
Bar, the most promising mitigation
measures available to the City of
Diamond Bar are those related
to the reduction of vehicle miles
traveled (VMT) through land use
and transportation planning that
promotes compact growth and
alternative modes of transportation.
This General Plan provides a land
use plan and corresponding land
use and circulation policies that act
as a framework for VMT reduction
through compact, mixed-use
development that provides greater
access to shopping, employment
and recreational destinations
that do not require travelling long
distances by car (see Chapter
2: Land Use and Economic
Development and Chapter 4:
Circulation). Other climate change
mitigation strategies include energy
efficiency and conservation, waste
reduction and diversion, and green
building and landscapes. Additional
measures to promote climate
change mitigation are outlined in
the City’s Climate Action Plan.
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COMMUNITY HEALTH AND SUSTAINABILITY
Diamond Bar is committed to helping reduce the
effects of rapid climate change. The City’s Climate
Action Plan (CAP) is designed to provide discrete
actions to operationalize the General Plan policies
that help with GHG reduction. The CAP outlines
Diamond Bar’s overall strategy to reduce GHG
emissions and identifies specific implementation
measures the City will undertake and quantifies their
impacts, in order to comply with State directives for
reducing GHGs. The California Assembly Bill (AB)
32 2017 Scoping Plan seeks to bring California to a
low carbon future, reducing emissions to no more
than six metric tons carbon dioxide equivalent
(MTCO2e) per capita by 2030 and no more than two
MTCO2e per capita by 2050. The AB 32 Scoping Plan
also directs local governments to assist the state in
meeting California’s emissions goals.
The GHG emission targets proposed for the Diamond Bar CAP are based on the
goals established by California Executive Order (EO) S-3-05 and SB 32, following the
CAP guidelines established in the 2017 Scoping Plan. The horizon year for analysis
in the proposed Diamond Bar CAP is 2040, corresponding with the General Plan
update horizon. Thus, the CAP will include targets of six MTCO2e per capita per year
by 2030 and four MTCO2e per capita per year by 2040 (derived from the Scoping
Plan target of two MTCO2e per capita per year in 2050). It provides a community-
based policy framework to address community-wide GHG emissions sources.
Specifically, the CAP is designed to:
• Translate high-level objectives and quantified goals into a realistic,
understandable set of implementation actions;
• Demonstrate that significant reductions in GHG emissions are
attainable through local actions;
• Inspire community members to work collectively to achieve these
reductions;
• Dovetail with General Plan policies that are required to address
climate change impacts and adaptation, including those for land use,
transportation, building design, and infrastructure; and
• Provide a predictable approach to mitigation strategies for the
compliance of future development projects with CEQA.
The CAP will be the primary tool for implementing the General Plan’s climate
change mitigation policies.
CLIMATE ACTION PLAN
COMMUNITY HEALTH & SUSTAINABILITY | Diamond Bar General Plan 20408-20
Energy Efficiency and
Conservation
Many energy efficiency and
conservation measures rely on
individual decisions and incentives
to make these decisions. The City
is positioned to act as a model of
energy efficiency and conservation
through the establishment of city
practices that reduce energy
consumption, and to disseminate
information on incentives such as
energy upgrading financing options
that will encourage the Diamond
Bar community to conserve energy.
Waste Reduction and Recycling
Diverting waste from landfills
by promoting reduction, reuse,
recycling, and composting of
materials can substantially reduce
greenhouse gas emissions. Recycling
and waste prevention programs
reduce energy and transportation
needed to manufacture and ship
resource-intensive products and
packing. Composting food and
yard waste reduces the amount of
methane produced in landfills.
Green Building and Landscapes
The California Green Building
Standards Code (CALGreen) was
adopted in 2010. It was the first
code of its kind to mandate green
building design and construction
in categories related to planning
and design, energy efficiency,
water efficiency and conservation,
material conservation and resource
efficiency, and air quality standards.
The City’s Building Code was
amended for consistency with
CALGreen Building Code. CALGreen
measures thus apply to all new
buildings (residential and non-
residential). In addition, Diamond
Bar’s biological resources and
ecosystems contribute to climate
change mitigation through carbon
storage and climate regulation.
These ecosystem services will be
particularly important as climate
change contributes to higher
temperatures and heat islands in
urban areas.
GREENHOUSE GAS EMISSIONS
GHGs are those compounds in the Earth’s
atmosphere that play a critical role in
determining temperature near the Earth’s
surface. More specifically, these gases allow
high-frequency shortwave solar radiation to
enter the Earth’s atmosphere, but retain some
of the low frequency infrared energy which is
radiated back from the Earth towards space,
resulting in a warming of the atmosphere.
GHGs result from human activities associated
with industrial manufacturing, vehicle
emissions, waste, and the use of electricity
generated from fossil fuels.
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CLIMATE CHANGE RESILIENCE
Although reducing GHGs is
necessary to avoid the most
catastrophic consequences of
climate change, a certain amount
of climate change within the
planning horizon of this General
Plan is unavoidable due to existing
emissions and the concentration
of GHGs in the atmosphere. The
Fourth California Climate Change
Assessment, completed in 2018,
projected that for the Los Angeles
region, including Los Angeles
County, changes in climate are
likely to include:
• Continued warming, with
average maximum temperatures
to increase 4 to 5 degrees
Fahrenheit (F) by 2050;
• Increases in extreme
temperatures, with the hottest
day of the year being up
to 10 degrees F warmer for
many locations by the end of
the century and the number
of extremely hot days also
increasing;
• Increases in both dry and wet
extremes, with increases in
precipitation on the wettest
day of the year and increased
frequency and severity of
atmospheric river events; and
• Increased frequency of wildfire.
In the Planning Area, some residents
will be more vulnerable to the
effects of climate change. For
example, young residents, seniors,
persons with disabilities, lower-
income households, those living in
social isolation, and the homeless
are at a much higher risk for health
problems related to heat and
wildfire smoke. Geographically,
some locations in the Planning
Area may be more susceptible to
certain effects of climate change.
Structures and residents located on
hillsides and near open spaces will
have greater wildfire risk. Intensively
developed areas are more likely to
experience “heat island” effects,
in which urban development and
human activities contribute to
higher temperatures than those in
surrounding unurbanized areas.
Heat islands are typically the result
of dark surfaces, building materials
that absorb and radiate heat, loss
of vegetation, and energy usage.
In order to reduce the community’s
vulnerability and build resiliency,
the City can prepare for and adapt
to the impacts of climate change.
Strategies can include the following:
• Plan for extreme weather
events by incorporating the
potential effects and threats of
climate change into emergency
management planning;
• Use urban design as a tool to
reduce heat island effects by
planting trees and limiting the
use of pavement, other urban
COMMUNITY HEALTH & SUSTAINABILITY | Diamond Bar General Plan 20408-22
materials, and human activities
that concentrate the sun’s heat;
• Create a system resilient to low
water supplies by managing
urban and agricultural water use
efficiently;
• Protect against failures of
the transportation system by
creating resilient transportation
systems with redundant, multi-
modal routes; and
• Build preparedness within the
community by ensuring that
community members are aware
of changing risks and have
access to necessary support
systems.
Many policies throughout this
chapter and other chapters of
the General Plan are intended to
increase the community’s resiliency
by promoting stability of different
ecological, social, built, and
economic systems of the City.
THE URBAN HEAT ISLAND EFFECT
Urban Heat Islands refer to developed areas that undergo higher warming
of the surface and the atmosphere than surrounding rural or undeveloped
areas. Research suggests that unmitigated Climate change will lead to
higher temperatures and longer, more severe, and more frequent heat
waves. Urban areas such as Diamond Bar already suffering from the heat
island effect will bear the brunt of these harsher heat events, increasing
the risk of illnesses such as heat exhaustion and heat stroke, particularly
among older adults, young children, and those who work outdoors.
Mitigation measures can include increasing the tree canopy, installing
green roofs and cool pavements, and reducing the number of vehicles in
an area.
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CLIMATE CHANGE AND GREENHOUSE GASES
See Chapter 4: Circulation for additional policies regarding
the reduction of VMT and promotion of multi-modal
mobility. See Chapter 5: Resource Conservation for
additional policies regarding hillside conservation and
open space preservation
GOALS
CHS-G-11 Promote initiatives that enhance sustainability
by reducing the community’s greenhouse
gas (GHG) emissions, protecting natural open
spaces which provide CO2 sequestration,
and fostering green development patterns,
buildings, sites, and landscapes.
CHS-G-12 Conserve natural open spaces by prioritizing
and supporting infill development
to build healthy, equitable, and
sustainable communities.
CHS-G-13 Promote energy efficiency and conservation in
the community.
CHS-G-14 Encourage waste reduction and diversion
practices to meet State targets
and reduce GHG emissions.
CHS-G-15 Increase the community’s resiliency and
capacity to resist and recover from social,
economic, and environmental disruption
from climate change impacts.
POLICIES
Greenhouse Gas Emissions
CHS-P-32 Continue to monitor the City's compliance with
State-mandate GHG emissions, as provided
for in the CAP. Make timely adjustments
to City policies as required to continue
meeting State GHG targets, and as changes
in technology, federal and State programs,
or other circumstances warrant.
COMMUNITY HEALTH & SUSTAINABILITY | Diamond Bar General Plan 20408-24
CHS-P-33 Encourage land uses to reduce vehicle miles
traveled (VMT), prioritizing infill development
and incorporating vertical and horizontal
mixed-use development, public transit,
and active transportation facilities
where appropriate, recognizing that
the transportation sector is the largest
source of GHG emissions in Diamond
Bar and in California more broadly.
CHS-P-34 Demonstrate City leadership in GHG emission
reduction activities by promoting incentives
for proposals that reduce or minimize
GHG production, or provide incentives for
selecting climate friendly, or lower and/
or non-emission producing alternatives.
E nergy Efficiency and Conservation
CHS-P-35 Use the City's CAP as the platform when
outlining and implementing measures
to improve energy conservation and
increase renewable energy use in
existing and new development.
CHS-P-36 Support and cooperate with local, regional,
State, and federal agencies on the
monitoring and evaluation of energy
resources as well as the identification
of energy-efficient and alternative
energy technologies and practices.
CHS-P-37 As opportunities arise, work with appropriate
federal, State, and private utility agencies
to identify and facilitate utility rate
revisions that would provide incentives
for the conservation of energy.
CHS-P-38 Promote the adoption of rooftop and parking
lot solar power and/or other alternative
energy usage on developed sites in
Diamond Bar through actions such as:
a. Establishing incremental growth goals for
solar power/alternative energy
systems in Diamond Bar;
b. Developing guidelines,
recommendations, and examples
for cost-effective solar and/or other
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GOALS & POLICIES
alternative energy-based installation; and
c. Installing solar/alternative energy
technology on existing City facilities.
CHS-P-39 Support Southern California Edison (SCE) and
Southern California Gas Company's
(SoCalGas) efforts to increase public
awareness of energy conservation
technology and best practices.
CHS-P-40 Require the inclusion, where feasible, of
provisions for energy-efficient modes of
transportation and fixed facilities that
establish public transit, bicycle, and
pedestrian modes as safe, efficient,
and desirable alternatives.
CHS-P-41 Support the use of clean fuel and "climate
friendly" vehicles in order to reduce
energy use, energy cost, and greenhouse
gas emissions by residents, businesses,
and City government activities.
CHS-P-42 Seek funding and other assistance from the
South Coast Air Quality Management
District for installation of electric vehicle
charging stations at appropriate
locations throughout the City.
CHS-P-43 E xplore participating in new high efficiency
technology programs such as LED lighting
for City facilities, safety lighting in parks and
other public spaces, and LED street lighting
conversion for all City-owned street lights.
CHS-P-44 Promote energy conservation and retrofitting
of existing buildings through the
implementation of the Green Building Codes.
CHS-P-45 Support and cooperate with the Walnut
Valley Water District, the Los Angeles
County Public Works Department, and
the Los Angeles County Sanitation
District in community education efforts
to reduce the consumption of carbon-
based fuels for conveyance and
treatment of water and wastewater.
COMMUNITY HEALTH & SUSTAINABILITY | Diamond Bar General Plan 20408-26
Waste Reduction and Recycling
CHS-P-46 In order to achieve compliance with the source
reduction goals set forth under Assembly Bill
(AB) 939 amendments thereto, incorporate
solid waste diversion goal performance
standards into the contracts with the City’s
franchise waste haulers, and enforce the City’s
Construction and Demolition Waste Ordinance.
CHS-P-47 Reduce the disposal of household hazardous
wastes in landfills through continued cooperation
with waste pick-up service providers, the
County Sanitation Districts, and the Los
Angeles County Department of Public Works
in the provision of curbside pick-up and
annual household waste round up events.
CHS-P-48 Continue to promote the safe disposal of
household hazardous waste through
public education and incentives.
CHS-P-49 Continue to educate residential, commercial,
and industrial generators about source reduction
and recycling programs and encourage
their participation in these programs through
promotional campaigns and incentives.
CHS-P-50 Encourage generators of edible food to have
contracts or agreements with food rescue
organizations to minimize edible food
from being disposed of or destroyed.
CHS-P-51 Encourage residents and businesses to compost
leaves, grass clippings, food waste, and
other organic materials by promoting existing
food waste pickup services, residential
waste hauler rate composting discounts,
and residential backyard composting.
CHS-P-52 Collaborate with the City’s contract waste
haulers to educate and encourage residents and
businesses about waste reduction strategies.
CHS-P-53 Support and cooperate with County and State
regulatory agency efforts to require commercial
and industrial generators to develop and
implement a source reduction and recycling
plan tailored to their individual waste streams.
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GOALS & POLICIES
Climate Change Resiliency
CHS-P-54 Incorporate updated information about future
climate change hazards, particularly
those related to extreme weather such
as drought, storms, heat waves, and
wildfires, into the City’s hazard mitigation
and emergency planning processes.
CHS-P-55 Encourage the protection and enhancement
of areas identified as healthy
functioning ecosystems that provide
the ecological, cultural, public health
and safety, and economic value of
ecosystem services, or benefits.
CHS-P-56 Prepare a Landscape Manual or otherwise
incorporate landscape standards in the
Municipal Code to mitigate urban heat
island effects and contribute to long-term
carbon storage through maximum tree
canopy coverage and minimum asphalt
and paving coverage particularly for
denser areas like the planned Town Center
and mixed-use neighborhoods, existing
shopping centers, and industrial and other
areas with expansive surface parking.
Consider the reflectance of stone and
rock ground cover in heat generation.
CHS-P-57 Encourage water conservation, drought-
tolerant landscaping and the use of greywater
and reclaimed and recycled water, where
appropriate, with a view to reducing water use.
CHS-P-58 Encourage the installation of green roofs and
cool (reflective) roofs to reduce temperatures
of roof surfaces and the surrounding air.
CHS-P-59 As resources become available, increase the
efficiency of water usage in public
places, such as irrigation in public parks,
and utilize drought-tolerant landscaping
in City parks and streetscapes.
CHS-P-60 Promote a resilient transportation system that
offers connectivity for multiple transportation
modes in the face of extreme events related to
climate change, such as storms and wildfires.
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1330 Broadway, Suite 604 T
Oakland, California 94612 F
415 956 4300
415 956 7315